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Geological reference material is a primary standard to ensure the accuracy of geological sample analysis results. After more than 40 years of development, China has developed and certified thousands of geological reference materials covering different media such as rock, ore, soil, sediment, organism, and water. China’s metrological management department divides the certified reference material into two classes according to the classification class, the first-class reference material (GBW) and the second-class reference material [GBW(E)]. According to their attributes and application fields, they are divided into 13 categories[6-7], and the geological reference materials belong to the seventh category [GBW07 and GBW(E)07]. It can be seen from the National Sharing Platform for Reference Materials (https://www.ncrm.org.cn) that by the end of the 13th Five-Year Plan, the total number of geological reference materials approved by the State Administration for Market Regulation is 1013, including 718 first-class certified reference materials, and the amount of first-class certified reference materials ranks first in the 13 categories (Fig.1). Geological materials are the most important and basic raw materials in the development of human society, with various types, complex components, and large differences in component content. It is because of the complexity of geological materials and the demand for reliable quantitative analysis that thousands of geological reference materials have been developed. Some reference materials developed by some industrial geological agencies are classified into other categories in classification management, such as isotope reference materials belonging to the fourth category, biological composition reference materials belonging to the tenth category, coal reference materials belonging to the eleventh category, these reference materials are widely used in related geological work, and in this paper they will be classified as geological reference materials. To systematically grasp the development status of geological reference materials in China, the first-class geological certified reference materials are comprehensively sorted, and are divided into six categories according to the type of matrix, property value and application scope: basic, ore, marine, environment, energy and special purpose (Table 1), and the development situation of each type, matrix characteristics and fixed value index respectively are summarized. On the basis of summarizing the results, on one hand, the main problems existing in the application of geological reference materials and the causes of these problems are analyzed. On the other hand, the detailed technical problems that may affect the uncertainty in the process of homogeneity, stability and characterization are discussed, and the views and suggestions are expounded. In this paper, the first-class geological certified reference materials are divided into the following six categories to summarize the development of each type: (1) 260 basic geological reference materials have been developed, the type of matrix including rock, soil and river sediments. The characteristic components of the certified value are generally 70 elements and compounds, which are mainly used as monitoring standards for sample analysis in basic geological surveys and research. (2) 272 ore geological reference materials have been developed, including precious metal ore, metal ore, single mineral, and non-metallic ore. The specific mineral types are shown in Table 1. There are generally 20 property values, which are the main technical indicators in mineral exploration. They are mainly used as a monitoring standard for geological exploration, mineral processing and smelting, comprehensive utilization, commodity inspection and trade amongst other fields. (3) 16 marine geological reference materials have been developed, including marine sediments and marine minerals. The specific samples include 10 marine sediment reference materials namely, 1 near sea, 1 Yellow Sea, 2 South China Sea, 1 East China Sea, 3 deep Pacific Ocean, 1 Antarctic Ocean and 1 Arctic Ocean. Six marine mineral reference materials are three polymetallic nodules and three ocean cobalt-enriched crusts. The characteristic composition of the certification value is the same as that of the basic geological reference material, but slightly less, generally 51-71 kinds. This is a necessary chemical composition measurement standard for marine sediment measurement and marine mineral resource survey and research. (4) 101 standard materials for environmental geology have been developed, including the available state of soil elements, the form of soil and sediment elements, the valence state of groundwater elements, the extractable state of soil elements, biological inorganic elements, organic pollutants in soil and sediment and other reference materials. The characteristic components of the matrix and certified values are the total amount of inorganic elements in biological samples, the available states, and forms of elements in soil and sediment, the valence states of elements in water and organochlorine pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons in soil and sediment. This kind of reference material provides analytical quality monitoring standards for land quality geochemical surveys and evaluation, regional ecological geochemical evaluations, multi-objective geochemical surveys and detailed surveys of soil pollution. (5) 23 energy geological reference materials have been developed. The property values of oil-generating rock reference materials are organic carbon, pyrolysis hydrocarbon S2, pyrolysis peak temperature Tmax, and chloroform asphalt “A”. The property values of coal reference material are calorific value, ash, volatile matter, total sulfur, carbon, hydrogen, nitrogen, true relative density and phosphorus, chlorine, fluorine, and arsenic. The property values of the reference materials of highly evolved hydrocarbon source rock are pyrolysis hydrocarbon S2, pyrolysis peak temperature Tmax, and total organic carbon TOC. This is the monitoring standard for the exploration, evaluation and rational utilization of energy and mineral resources. (6) 129 reference materials for special purposes have been developed, including 20 synthetic reference materials for emission spectroscopy and 4 synthetic reference materials for X-ray fluorescence spectroscopy analysis. The property values are 28-29 inorganic chemical elements. There are 38 isotope reference materials, and the property values of those include isotope abundance and abundance ratio. There are 35 electron probe reference materials, and the property values are generally two principal components of their minerals. There are 15 reference materials for phase analysis, and the property values are the corresponding main phase. There are 5 soil limit water content reference materials, and the property values are 10mm liquid limit, plastic limit, and plastic index. There are 12 soil pH reference materials, and the property values are pH. It can be seen from the classification and summary that the geological reference material matrix in China is rich in types and quantities, which establishes an influential quality monitoring system for geological sample analysis, ensures the reliability and consistency of geological sample test data, and significantly improves the comparability and scientific value of relevant data. At present, there are still some problems in the application and development technology of a large number of geological reference materials. The problems are discussed and analyzed, hoping to draw attention to improving the value determination class of geological reference materials. In the aspect of application, the specific problems existing in different types of geological reference materials and their causes at the present stage are analyzed and development suggestions are proposed, according to the work needs of current mineral resources, international cooperation, marine strategy, ecological civilization and other fields. In the aspect of development technology, some detail technologies which may affect the value determination class in the process of homogeneity, stability and characterization are analyzed. In the aspect of development technology, some detail technologies which may affect the setting in the process of homogeneity, stability and value setting are analyzed. The test method of homogeneity and the evaluation method of stability uncertainty are discussed. Suggestions are made for the uncertainty evaluation method of unexamined elements for homogeneity test and control limit of relative extended uncertainty. 1. Three problems existing in the current application of geological reference materials are analyzed: (1) The quantity of some types of reference materials developed is small, the gradient distribution of characteristic values is insufficient, and the matrix type is simple. For example, the amount of marine geology, micro-area analysis, energy and mineral resource reference material development is small. The ore-forming elements of key metal ore reference materials are mainly low content, lacking rich ore grade or higher content grade. The matrix types of the samples of organic pollutant reference materials are only soil and sediment, and the property values are only organochlorine pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons and other compounds, and the matrix types and target compounds are few. The main reasons for these problems are difficulty in obtaining samples, little working demand, difficulty in ensuring the uniformity and stability of the sample preparation technology, large error of analysis technology unable to determine the value. (2) There are many components in the geological reference materials with mature development technology that have no certified values. The reasons of low element content and test interference are mainly analyzed. (3) At the current class of analytical technology, there is only one measurement method for several elements, and for some elements, with the widespread application of modern instrumental analysis technology, the optional measurement method is gradually becoming singular. 2. The detail technology of four aspects in the development of reference material is discussed: (1) Uniformity testing method. XRF is a widely used measurement method for the uniformity test of geological standard materials due to its high testing precision. However, due to its large sample size, XRF cannot meet the requirements of minimum sample size. Since the release and implementation of China National Technical Specification for Measurement “General and Statistical Principles for Characterization of Reference Materials” (JJF1343) in 2012, the uniformity of reference materials was tested by ICP-MS and ICP-OES under 0.1g weighing sample[24-30]. The measurement precision of these two methods is not as good overall as that of XRF, and the accuracy of individual elements is poor, which may cause the numerical value to be too large when calculating the uncertainty introduced by uniformity, thus affecting the reasonable evaluation of the uncertainty of property value. For this reason, some scholars[34-35] improved the XRF sample preparation device, studied the accuracy and precision of the method under 0.1g weighing sample, and verified the application effect for uniformity testing. However, only 10 major components in the reference materials of soil and stream sediments were tested under 0.1g weighing sample, while the reference materials of other matrix types and other trace elements, especially heavy elements, have not been studied and tested. Therefore, the feasibility of the XRF method with a sample size of 0.1g still needs to be verified. (2) Uncertainty calculation method for elements without uniformity test. The composition of geological materials is complex, and its reference substances generally have multiple attribute values, and the content of each component is greatly different, so it is usually difficult to test the uniformity of all attribute values. According to the provisions of JJF1646—2017, the characteristic of representative and less homogeneous should be selected for uniformity evaluation. The uncertainty of the untested elements can be evaluated according to the concentration and geochemical properties with reference to the uncertainty introduced by the tested elements. However, the exact calculation method was not specified. An evaluation method that considers both element properties, content and test methods (Table 2) is presented here. The specific calculation method is to multiply the relative uncertainty (Ur) of the uniformity of the detected element by the standard value μ of the undetected element and take it as the uncertainty component ubb of the undetected element. (3) Evaluation method of stability uncertainty. At present, trend analysis method is generally used to evaluate the stability uncertainty (us) of geological reference materials, and the calculation formula is us=s(b1)·t. It can be seen from the formula that the longer the stability monitoring time, the greater the stability uncertainty introduced. The stability uncertainty data of several reference materials were compared and determined to be the main contribution to the total uncertainty, which is inconsistent with the long-term observation of the stability of the geological reference materials. Therefore, this calculation method is not suitable to evaluate the uncertainty introduced into the stability of geological reference material. Meng et al.[42] suggested using the analysis of variance to calculate, and the comparative analysis showed that us was still the main contribution to the total uncertainty. Wang et al.[43] used range method to calculate us, but the application of this method in geological reference materials has yet to be verified. In conclusion, the reasonable evaluation of stability uncertainty of matrix reference materials with more test error sources needs to be studied further. (4) Control limits for relative extended uncertainty. The determination of the property value of geological reference materials usually has certain control requirements for relative extended uncertainty (Urel), but these control limits are rarely introduced in the public information of the reference material. It was not until the specification JJF1646 published in 2017 that Urel was required in principle. Urel is the embodiment of the quality of property value data. Urel control limits in Table 3 are proposed on the basis of the principle requirements of JJF1646—2017 by referring to the control limits in the development of existing reference materials and the analysis of different types of geological reference materials. In the process of development, the developer also needs to comprehensively consider the matrix condition, setting index, element content of the sample and formulate reasonable Urel control limits of uncertainty in combination with the current analysis technology class, to obtain accurate and reasonable property value and uncertainty.

BACKGROUND Sulfur is an active element with multiple chemical forms, which plays a vital role in the regulation of redox chemistry. Reduced inorganic sulfur (RIS) including acid volatile sulfur (AVS), elemental sulfur (ES) and pyrite sulfur (CRS) is the most active part of sulfur species in sediments and plays an important role in controlling the geochemical behavior of iron, phosphorus and heavy metals in sediments. Separation and determination of reduced inorganic sulfur in anoxic sediments are critical to ecological and geological studies of sulfur cycles.Both distillation and diffusion methods can be effectively used to separate AVS, ES, and CRS in sediments. However, the current methods for extracting sulfur species are difficult to adapt to the large number of samples in geological and environmental research. Due to the reaction time, requirements of 24h for single sulfur species in the diffusion method limits the number of samples that can be processed on a timely basis. This limitation presents a problem for analyzing fresh anoxic sediment samples which have to be processed immediately to minimize the risk of sulfide re-oxidation. The detection method has the disadvantages of having a cumbersome testing process, long analysis time, and easy loss of sulfur components. OBJECTIVES To achieve efficient and continuous determination of reduced inorganic sulfur forms in bulk sediment samples. METHODS The method used in this experiment was improved based on the thermal distillation method, which was used to continuously extract the reduced inorganic sulfur from sediments. The reaction flask used in the experiment was a three-head round-bottom flask. A nitrogen flushing pipe, a condenser tube and two injection tubes were connected to each of the small necks. For the AVS procedure, 1.00g sediment sample reacted with 10mL of 6mol/L HCl under nitrogen gas at an elevated temperature (90℃) to convert reduced sulfur species into hydrogen sulfide which was subsequently carried by a nitrogen gas stream into a trap. For the CRS procedure, 20mL of CrCl2 solution was added to the sediment in the distillation flask after the AVS procedure, and 10mL of 6mol/L HCl was immediately placed in the flask at an elevated temperature (90℃), flushed with nitrogen. For the ES procedure, 20mL DMF were poured into the sample flask which contained acid and CrCl2 solutions from the previous procedure. 20mL of CrCl2 solution and 10mL of 6mol/L HCl were injected into the flask, and the reaction was allowed to take place at 90℃ purging with nitrogen. During the entire distillation process, H2S gas was absorbed by NaOH solution, and then oxidized by H2O2 to SO42-. The concentrations of SO42- were obtained by ion chromatography. RESULTS Repeatability experiments (n=3) were conducted on sediment samples from the Three Gorges Reservoir area and the mean values of acid volatile sulfur, elemental sulfur and pyrite sulfur were obtained as 0.19, 0.37 and 3.10μmol/g, respectively. The relative standard deviations (RSD) of the experimental results were 5.26%, 1.22% and 3.09%, respectively. In order to test the effectiveness of the distillation procedures, Na2S·9H2O, pyrite and S were added in the sediment to reveal the corresponding standard recoveries. An average of 92.8% of the added Na2S·9H2O was recovered by the AVS diffusion method. An average of 93.6% of the added pyrite was recovered by the CRS diffusion method. An average of 94.1% of the added elemental sulfur was recovered by the ES diffusion method. In the literature, recovery of AVS by the improved diffusion method ranged from 82.01% to 108.71%, and recovery of ES ranged from 92.25% to 98.08% (n=3), respectively.The modified apparatus presented in this paper was an economic version which uses rubber and glass parts. The method provided the advantages of lower sample weighing, and simple operation. Compared with the diffusion method (24h), the extraction time for individual sulfur forms by our distillation method was just 1.5h. The recoveries achieved by the method are comparable to those reported for earlier methods. In addition, the results are more like the data on reduced inorganic sulfur content obtained by Hongbin Yin after measuring sediment samples from Taihu Lake using the modified cold diffusion method, indicating that the method designed in this study has a high degree of confidence.Geochemical processes of sulfur in river aquatic systems play a crucial role in environmental evolution. In this study, the distributions and seasonal variation of reduced inorganic sulfur (RIS) in the Three Gorges Reservoir area surface sediments were investigated. Surface sediment samples were collected from 8 points in the section from Yunyang to Zigui in the Three Gorges Reservoir area in August and December 2017. The result showed that the AVS and ES contents were higher in summer than in winter, and the trend of RIS in the section from Yunyang to Zigui was roughly decreasing, with obvious seasonal and spatial changes. Low sulfur pollution in the Three Gorges Reservoir area was observed. CONCLUSIONS The improved thermal distillation method and apparatus in this study have significant advantages in the extraction efficiency of reduced inorganic sulfur from sediments. The extraction time of this study for individual sulfur form is 1.5h, less than the diffusion method. The established analytical method has good precision and accuracy, which is suitable for investigation studies with large numbers of samples such as environmental research and geological surveys.

BACKGROUND With the continuous accumulation of data resources around the world, the application of data visualization has become more urgent, and the methods of data visualization have also shown diversified characteristics. Data visualization is a scientific and technical research on the visual representation of data, which studies how to display relatively obscure data visually in a real and accurate way, to vividly and intuitively express the information and rules contained in the data. Literature is an important carrier of knowledge dissemination, with systematic characteristics, continuity, a large quantity and fast update, and is an important source of information. The visualization research of literature is of great significance to the dissemination of knowledge. At present, the visualization research of document data is mostly combined with the bibliometric analysis method, which visualizes the relationship between documents in the form of a scientific knowledge map. The application of this technology and method has played an important role in mining the information and rules contained in document data, but it is slightly insufficient in the spatial attribute mining of document data, which requires in-depth research in this field. OBJECTIVES To provide new solutions for expanding the application of literature data in the field of spatial visualization, thereby further enhancing the usable value of literature data. METHODS GIS technology was used to carry out the research on the spatial visualization method of document data, excavate the common content features and spatial features of document data, and gather the structured document data of a certain volume of spatial feature information to lay the data foundation for the visualization research. At the same time, the combination point between GIS technology and document data was studied, and the strategy and technical route for information mining and spatial visualization of document data were formed. Taking the data of more than 140 Re-Os isotope dating documents published since 2015 to 2020 as an example, the application test of this technical method was carried out. A Re-Os isotope data visualization service system with a five-tier architecture including layers of support, data, service, application and user has been developed, to realize the spatial visualization application of Re-Os isotope dating document data results. RESULTS The results show that: (1) The study area contains more than 140 ore producing areas that carried out Re-Os isotope dating research from 2015 to 2020, covering the eastern, central, and western regions of China. (2) There are 19 main minerals in the study area, mainly copper (29.0%), molybdenum (28.3%), tungsten (12.4%) and gold (11.0%). (3) There are 12 kinds of detection objects, and the proportion of molybdenite as the detection object is 80.7%, which indicates that molybdenite is still the preferred research object of the Re-Os isotope dating method, which is inseparable from the high Re/Os value of molybdenite. (4) The detection age falls in the lower age range of 0-200Ma, accounting for 62.1% of the ore-producing areas, which are mainly distributed in the northeast and southeast regions of China, indicating that the Re-Os isotope ages in the eastern region are concentrated in the Mesozoic era, which is consistent with the existence of large-scale Mesozoic mineralization events in the eastern region of China. The ore-producing area in the age range above 200Ma accounts for 37.9%, which is mainly distributed in the central and western regions of China, indicating that the Re-Os isotope ages in the central and western regions are concentrated before the Mesozoic era and have the characteristics of multiple mineralization. CONCLUSIONS The research shows that the document data visualization technology and method proposed in this paper can be used to excavate the spatial characteristics of the document data, expand the application of the document data in the field of spatial visualization, and solve the problems of how to analyze and extract the common information of the document data, locate the spatial feature information, and realize the spatial visualization technology. In terms of revealing important target areas, key research minerals and main application technologies, it can provide spatial visualization information, and provide reference for finding the hot spots and difficulties of current metallogenic chronology research.

BACKGROUND The emerald is loved by people because of its gorgeous color and is respected as one of the world's four major gems. Due to the high value of emeralds, a variety of synthesis and optimization methods have emerged. The hydrothermal method is one of the common methods to produce synthetic emeralds. The emeralds synthesized by this method have typical water ripple texture, showing a serrated parallel arrangement, and the characteristic peaks of the infrared absorption spectrum in the range of 2300-3100cm-1 are the main identification feature. However, some emeralds synthesized by this method do not have the above typical characteristics. This has brought a great challenge to the quality inspection agencies, and brought many doubts to the majority of consumers, and affected the stability of the gem market. OBJECTIVES It is essential to study the new emerald synthesized by this new hydrothermal method. The refractive index, density, polychromatism, and infrared absorption spectrum characteristics of the tested samples are very similar to those of natural emeralds, so infrared absorption spectrum analysis cannot obtain the supporting evidence of its cause. Based on this, the gemological and spectral characteristics of the test samples were studied by ultraviolet visible spectrum, energy dispersive X-ray fluorescence spectrometry (EDXRF) and other spectroscopic means. Finally, the test samples were determined to be a new kind of emerald synthesized by the hydrothermal method. METHODS The refractive index, birefringence, relative density, polychromaticity and weight of the samples were tested by refractometer, electronic balance, and dichroic mirror. The internal and external characteristics of the test samples, the cutting and polishing quality of the samples, and the characteristics of internal inclusions were observed by gem microscope. The infrared reflection spectrum and infrared transmission spectrum characteristics of the samples were analyzed by Fourier transform infrared spectrometer and compared with the infrared spectrum characteristics of emeralds from different origins. The absorption spectrum characteristics of the samples were analyzed by ultraviolet-visible spectrometer, focusing on the absorption peak characteristics near 830nm. The element characteristics of the samples were tested by EDXRF, because the content characteristics of Cr and Ni in emerald are the key to identify whether it is natural or not. RESULTS The mass of the tested samples was 0.17-0.56g, the refractive index was 1.571-1.588, the birefringence was 0.007-0.009, the relative density was 2.56-2.78, and the polychromaticity was obviously blue-green/green. These conventional gemological characteristics were consistent with natural emeralds. The samples were observed under a gemstone microscope, and the samples had a parallel texture of suspected water ripple, but not typical. The water ripple texture of the typical hydrothermal synthetic emeralds was serrated parallel arrangement. However, the characteristics under the gem microscope should arouse the suspicion of jewelry inspectors.The infrared reflectance spectra of the samples had characteristic peaks of 1242, 1219, 1022, 968, 810, 741, 687, 594, 528, 490, and 459cm-1. The characteristic peaks of 1242, 1219, 1022, 968, 810, 741, and 687cm-1 were caused by the stretching vibration of Si—O—Si and O—Si—O, and the characteristic peaks of 594, 528, 490, and 459cm-1 were caused by the bending vibration of Si—O and the vibration of M—O. The infrared reflection spectrum characteristics of the samples were consistent with the infrared spectrum characteristics of beryl, but the infrared spectrum characteristics of the fingerprint area could not indicate whether the samples were natural or synthetic.The infrared transmission spectra of the samples had 5445, 5273, 5109, 4874, 4800, 4650, 4547, 3321, 3222, 3027, 2953, 2928, and 2431cm-1 characteristic peaks. 5273cm-1 was caused by typeⅡ water absorption, 5445cm-1 and 5109cm-1 were caused by typeⅠ water absorption. The typeⅡ water absorption peak of the test samples was relatively sharp at 5273cm-1, and the typeⅠ water absorption peaks at 5445cm-1 and 5109cm-1 were relatively strong. Compared with previous studies, the shape and intensity of water absorption peaks of natural emerald and hydrothermally synthesized emerald were different. The infrared absorption spectrum characteristics of the water of the test sample were different from those of natural emerald, but the diagnostic direct evidence could not be obtained from the infrared absorption spectrum. The infrared peak in the range of 2300-3100cm-1 is caused by Cl- ion absorption. According to the results of previous studies, the absorption intensity of hydrothermal synthetic emeralds in this wavenumber range was significantly stronger than that of natural emeralds. The infrared absorption spectra of the test samples were relatively weak in the range of 2300-3100cm-1, which was more similar to the infrared absorption spectrum characteristics of natural emeralds in Colombia, Yunnan, Madagascar and Brazil, and was obviously different from the infrared absorption spectrum results of emeralds synthesized by the hydrothermal method. There were obvious differences between the infrared transmission absorption spectra of the traditional hydrothermal synthetic emeralds and natural emeralds. The characteristics of infrared absorption spectra are important evidence for identifying the genesis of emeralds. However, it is difficult to obtain the final accurate conclusion from the infrared absorption spectrum analysis of the test samples described in this paper, so they have been named 'new' type.The UV-Visible spectrum characteristics of the test samples showed that the absorption peak below 350nm was caused by the Fe2+-O2- charge transfer band in emerald, the absorption peak at 429nm was caused by Cr3+ ions, the broad absorption band at 550-650nm was mainly caused by Cr3+ ions, the absorption peak at 683nm was caused by Cr3+ ions, the sharp absorption peak at 956nm was caused by water absorption, and the broad absorption peak near 850nm should be caused by Fe2+ absorption, which was rarely seen in the previous hydrothermal synthesis of emerald. The combination of Cr3+ and Fe3+ replacing Al3+ makes emerald, green. The absorption peak of UV-Visible spectrum caused by Fe2+ in natural emerald was in the range of 810-850nm, and only a few of the absorption bands caused by Fe2+ in natural emeralds are not obvious. The absorption band of the UV-Visible spectra of the test samples was not obvious or weak in the range of 810-850nm, and the 850nm absorption peak of individual samples was obvious. Therefore, the emeralds examined by ultraviolet-visible spectroscopy may be synthetic, but this could not be conclusively confirmed.The EDXRF results showed that the samples had Fe, Ni and Cr elements, which was different from previous studies of natural emeralds. Yang Zhuo(2010) studies showed that the main trace elements in natural emeralds, from different origins such as Brazil, Colombia, Egypt, India, South Africa, Zimbabwe and Canada by LA-ICP-MS, were Fe, V, Cr, Mg, Na and Cs, but the content of Ni was very low, far lower than that of Cr. The content of Cr in Yunnan emeralds was 58-177μg/g, and Ni was not detected (Bai et al., 2019). The chemical element characteristics of gem-grade emeralds in Afghanistan, Brazil, Colombia, Ethiopia, Madagascar, Russia, Zambia and Zimbabwe showed that Ni element was not detected (Karampelas et al., 2019). The elemental composition of emeralds from South Africa, Afghanistan, Australia, Colombia, Egypt, Madagascar, Zambia, Zimbabwe, Tanzania and China was analyzed by electron probe microanalysis, and Ni was not detected (Lum et al., 2016). It could be seen that Cr and Fe elements coexisted in natural emeralds, but Ni was almost non-existent. EDXRF was used in this study without quantitative analysis but calibrated by the gold standard sample, and the relative peak intensity of the element was of great significance. The peak intensity of the Ni element in the test sample was much higher than that of the Cr element, which did not conform to the element content characteristics of the natural emerald, and was consistent with the high content of Ni in the hydrothermal synthesis of emerald reported by Lu and Shen (2021) and Yang et al.(2022). The comprehensive analysis showed that the test sample was a synthetic emerald. CONCLUSIONS The infrared absorption spectrum characteristics of the test samples are similar to those of natural emeralds, and the infrared absorption spectrum could not be used as a basis for identifying the genesis of emeralds. Previous studies show that a set of absorption peaks in the range of 2300-3100cm-1 in the infrared absorption spectrum is an important identification feature of the hydrothermal synthesis of emeralds, but this feature is not obvious in the tested samples. The UV-Visible spectrum of the sample shows that the absorption band near 810-850nm related to Fe2+ is not obvious. The X-ray fluorescence spectra of the samples show that the Kα peak intensity of Ni is much higher than that Kα of Cr, which is the main feature of the new emerald synthesized by the hydrothermal method. It could be seen from the experimental results that the identification of jewelry and jade is a systematic work. It is necessary to learn from the previous results and combine the comprehensive analysis of various detection methods to obtain the correct result.

Plant growth regulators (PGRs) are defined as naturally occurring or artificially synthesized compounds. The functions of PGRs mainly include accelerating or delaying seed germination, breaking plant dormancy, stimulating or reducing bud elongation, inducing flowering and fruiting, and affecting the aging process. The application of PGRs has effectively promoted the growth of plants. However, the application concentration of PGRs is more than one millionth. The large amount of abuse and misuse of PGRs in the process of use not only reduces the yield of crops, but also exacerbates their residues in the environment, especially in agricultural products such as fruits and vegetables. So, they are detected in many environmental media like fruits, vegetables, and water. In addition, most PGRs are toxic, and some of them will undergo adsorption, desorption, hydrolysis, photolysis, microbial degradation, and other environmental behaviors after entering the soil. The decomposition products produced by this process are more toxic.In order to comprehensively understand the current status of PGRs pretreatment, analysis and test method, the common pretreatment methods of solid phase extraction and liquid-liquid extraction for typical PGRs in solid substrates such as fruits and vegetables, fertilizers and soil, and in liquid substrates such as water, edible oil and nutrient solution are summarized in this paper, as well as the analysis and testing techniques such as high-performance liquid chromatography (HPLC) and ultra-high performance liquid chromatography (UPLC). Moreover, to reduce the detection limit, high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) is also frequently used. At the same time, considering the strong natural attenuation ability of PGRs and the high toxicity of their intermediates, the advantages, disadvantages and applicability of different testing techniques are systematically summarized, taking into account the special structure and nature of PGRs, in order to fully understand the current status of pretreatment and analytical testing of PGRs and provide literature support for subsequent research on analytical testing, migration transformation, pollution evaluation and treatment of PGRs.Due to many impurities in the sample that can interfere with the detection, the appropriate pretreatment method can improve the accuracy of the test results. However, the sample pretreatment process accounts for more than 70% of the total analysis and test work, and about 50% of the error in the final test results comes from pretreatment. Therefore, establishing a fast, simple, and stable pretreatment method can effectively improve the efficiency and accuracy of analysis and detection. At present, the forms of environmental media detected for PGRs are mainly divided into two types: solid matrix samples (such as fruits, vegetables, fertilizers and soil, etc.) and liquid matrix samples (water, oil and nutrient solution, etc.). The related pretreatment methods are also mostly targeted at these two different forms of environmental media.Solid substrates involving PGRs mainly include fruits and vegetables, fertilizers and soil. Among them, fruits and vegetables are the most frequently detected solid substrates of PGRs, and some PGRs have also been detected in fertilizers, soil and other substrates. The pretreatment process of solid matrix samples can be divided into two parts: extraction and purification. Among them, solid phase extraction is the most commonly used extraction technology, and QuEChERS method is the most widely used purification method.Water, edible oil, and nutrient solution are the most frequently detected liquid substrates of PGRs. At present, liquid-liquid extraction is the most commonly used extraction method for liquid matrix. For the selection of extractants, the octanol-water partition coefficient of PGRs such as gibberellic acid and ethephon is less than 1, which is a strong polar compound and can be extracted by hydrophilic organic solvents such as methanol, ethanol and acetone; the polarity of most other PGRs such as forchlorfenuron and paclobutrazol is relatively weak, but it still belongs to the category of strong polarity compared with other kinds of compounds such as benzene and chloroethane (n-octanol-water partition coefficient>10). Therefore, the extractant can not only use methanol, but also use polar organic solvents such as ethyl acetate and chloroform that are insoluble in water. Although liquid-liquid extraction requires a lot of extractants, the high-water solubility of most PGRs makes them often directly detected by HPLC-MS/MS, which eliminates the complex pretreatment steps such as extraction and purification. In addition, because some PGRs have poor chromatographic characteristics or are not easily detected, the derivatization is also required to convert the components into derivatives suitable for analysis.Analytical and testing technologies mainly include gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS), HPLC/UPLC, HPLC-MS/MS, ion chromatography (IC), spectrophotometry (SP), capillary electrophoresis (CE), enzyme-linked immunosorbent assay (ELISA) and electrochemical sensor method.At present, the solubility of most PGRs in water (20℃) is 0.50-10g/L, and the octanol-water partition coefficient of most PGRs is 0-4, with strong hydrophilicity. Therefore, HPLC-MS/MS are applicable to the detection of almost all PGRs. However, HPLC-MS/MS are often used to detect the residues of PGRs in fruits and vegetables, followed by soil and fertilizer, while there are few related studies in natural water. This may be due to the rapid natural decay rate of PGRs in the natural environment, resulting in extremely small amounts of residues in natural water bodies such as surface water and groundwater that cannot be directly detected.GC has the advantages of low cost and easy maintenance, and GC-MS has become a conventional testing technology. However, GC-MS are greatly affected by sample matrix interference and require high pretreatment methods. In addition, due to the influence of the physical and chemical properties of different PGRs (such as abscisic acid and indole acetic acid with a boiling point over 400℃, or forchlorfenuron and cinnamic acid with hydroxyl and carboxyl groups), most PGRs have poor gas chromatographic characteristics and are not easily detected.The order of detection limits of PGRs is GC>HPLC>chromatography-mass spectrometry, and the lowest instrumental detection limit of chromatography-mass spectrometry is 10-5mg/kg. However, the higher solubility and the larger natural attenuation rate of most PGRs lead to the lower detection concentrations in complex environmental substrates such as soil and water, so there is still an urgent need to solve the problem of analytical testing of trace PGRs and its intermediates.In future, PGRs analysis and test method will focus on the analysis and detection of trace PGRs and their intermediates, as well as the development of new materials and technology-based methodologies.

BACKGROUND With the wide application of iridium and rhodium in aerospace, electronics, energy and other fields, it has become a very attractive metal in the world. In China, iridium and rhodium ore resources are relatively scarce with low grade, so it is essential to recover iridium and rhodium from secondary mineral resources. Copper anode slime enriches most of the precious metals such as iridium and rhodium in ores, which has high comprehensive recovery value. At present, there is no detection standard for iridium and rhodium in copper anode slime. The migration behavior of iridium and rhodium was not clear, so it was difficult to achieve directional enrichment and efficient extraction of iridium and rhodium metals. Therefore, the development of detection methods for iridium and rhodium in copper anode slime is an important prerequisite for the recovery and extraction of iridium and rhodium. OBJECTIVES An analytical method for accurate determination of iridium and rhodium in copper anode slime was established to maximize the utilization of mineral resources and the recycling rate of iridium, rhodium and other precious metals. At the same time, it could provide data support for the purification of iridium and rhodium in copper anode slime. METHODS In this paper, a method for determination of iridium and rhodium in copper anode slime by inductively coupled plasma-mass spectrometry (ICP-MS) with nickel sulphide fire assay was established. In the experiment, the precious metals iridium and rhodium in the sample were captured by nickel sulphide fire assay. The NiS beads were dissolved with 50% hydrochloric acid so that the precipitation of rhodium and iridium was separated from silver and other impurity elements through filtration when it was hot. The precipitates containing iridium and rhodium were effectively separated from silver and other impurity elements. The precipitate of iridium and rhodium with filter film were transferred into a closed digestion tank and dissolved in 50% aqua regia. The contents of iridium and rhodium in the solution were directly determined by ICP-MS. RESULTS The conditions such as the ingredient of nickel sulphide fire assay, the concentration of hydrochloric acid, tellurium coprecipitation, the sealing digestion time and temperature were studied. The experimental results showed that the molten slag was acidic when the ratio of nickel to sulfur was 4∶1, and it could effectively capture the iridium and rhodium in the sample with good fluidity of molten slag and the separation effect of slag buckle. When the NiS beads were dissolved by 50% hydrochloric acid, the dissolution reaction of NiS beads was suitable and complete. The precipitation containing rhodium and iridium was separated from impurity elements and filtered when hot. The precipitation was sealed and digested by dilute aqua regia (1∶1) at 160℃ for 2-3h. The possible MS interference was eliminated by selecting a suitable determination isotope. The 185Re was selected as the internal standard of 103Rh and 203Tl as the internal standard of 193Ir to eliminate the effect of signal drift, the results of iridium and rhodium had high precision and accuracy. The standard solution series of iridium and rhodium were determined under the optimized experimental conditions. The results indicated that the mass concentration of iridium and rhodium in the range of 10-100μg/L were linear to the ratio of the intensity of iridium and rhodium to the internal standard mass spectrometry. The calibration curves of iridium and rhodium were y=36674.6x+8264.7 and y=45686.7x+288.6, respectively, and the linear correlation coefficient (r) of calibration curves of iridium and rhodium were more than 0.999. The detection limits for iridium and rhodium were 0.007μg/L and 0.011μg/L, respectively, and the lower limits of detection were 0.024μg/L and 0.038μg/L, respectively. The content results of rhodium and iridium in 8 actual samples with the method showed that, the relative standard deviation (RSD, n=7) was between 1.40% and 4.57%, and the recovery was in the range of 95.00% to 103.65%. CONCLUSIONS The method has high efficiency and accuracy and can meet the detection requirements of copper anode slime samples.

BACKGROUND With the comprehensive development of the agricultural ecological geological survey and the improvement of people's attention to the ecological environment in our country, the demand for biogeochemical reference materials in biological analysis food analysis and agricultural products analysis is increasing. The existing biogeochemical reference materials are in short supply, and there is an urgent need to develop new reference materials. With the full deployment and development of agro-ecological geological surveys, the demand for biogeochemical reference materials is increasing. OBJECTIVES To reproduce tea composition reference materials (GBW10016a & GBW10052a) to take the place of old tea composition reference materials (GBW10016 & GBW10052). METHODS According to the development needs of geological surveys, the focus of this paper is on the preparation of two tea reference materials, GBW10016a and GBW10052a. The progress includes sampling, processing and preparation, particle size test, uniformity test, stability test, content test, and calculation of identification value and uncertainty.In the sampling process, the sample collection locations are Wuyishan City, Fujian Province and Wuyuan County, Shangrao City, Jiangxi Province. The candidates are oolong tea and green tea. The tea samples both weigh 400kg.In the processing and preparation, the samples were cleaned, freeze-dried, heated and dried, ball milled, screened, sub-packed and inactivated. In the particle size test, the BT-9000s laser particle size distributor was used to test the particle size of the samples. The particle size of GBW10016a & GBW10052a centrally distributed in the range of 75μm to 200μm, and the cumulative distribution content reached 98% in the range of 175μm to 200μm.In the uniformity testing process, 15 bottles of samples were randomly selected for analysis of more than 30 elements. The analysis results show that the relative standard deviation of the elements is less than 7%, the measured values F in the variance test are less than the critical value F. It shows that the uniformity of the samples is acceptable.In the stability testing process, the short-term and long- term stability of the samples are good according to the analysis and testing in different time periods.In the content testing process, a total of 61 indicators were analyzed by accurate and reliable methods such as inductively coupled plasma-mass spectrometry/optical emission spectrometry (ICP-MS/OES) and atomic fluorescence spectrometry (AFS) in multiple laboratories.In the process of calculation of identification value and uncertainty, the Grubbs algorithm and the Dixon algorithm were carried out to check and exclude individual out-group data in the group at the first step. The Cochrane algorithm was used to carry out precision testing at the second step. The Shapiro-Wilk algorithm was used to complete the data normality test.The whole preparation process of the tea reference materials follow three specifications: Technical Norm of Primary Reference Materials (JJG 1006—1994), General and Statistical Principles for Characterization of Reference Materials (JJF 1343—2012) and The Production of Reference Materials for Geoanalysis(JJF 1646—2017). RESULTS GBW10016a (GSB-7a) and GBW10052a (GSB-30a) tea reference materials are successfully reproduced, and have been approved as national first-class reference materials. The GBW10016a (GSB-7a) and GBW10052a (GSB-30a) are characterized by strong representativeness, multi-component planting, and accurate and reliable customization results. A total of 61 indicators are involved in this reproduction: Ag, Al, As, B, Ba, Be, Bi, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Er, Eu, F, Fe, Gd, Ge, Hf, Hg, Ho, I, K, La, Li, Lu, Mg, Mn, Mo, N, Na, Nb, Nd, Ni, P, Pb, Pr, Rb, S, Sb, Sc, Se, Si, Sm, Sn, Sr, Tb, Th, Ti, Tl, Tm, U, V, Y, Yb, Zn. GBW10016a (GSB-7a) contains 54 elements with certified values and uncertainties, and 3 elements with reference values. GBW10052a (GSB-30a) contains 57 elements with certified values and uncertainties, and 3 elements with reference values. For GBW10016a (GSB-7a), Ag and Sn are added, and Ge and Tl are upgraded from the reference values of the original batch (GBW10016) to the certified values. For GBW10052a, Al, Ag, Cl, I, N, S, Sb, Sc, Si and Sn are upgraded from the reference values of the original batch (GBW10052) to the certified values. Due to the current level of analysis technology and objective conditions, the elements of Hf and Nb cannot be given reference values. CONCLUSIONS The reference materials effectively support the needs of geochemical investigation and evaluation of the agricultural ecological environment, analysis of biological samples and food and agricultural products. With the development of ecological environmental research and food safety and hygiene inspection, people pay more and more attention to the characteristic elements, and the requirements are increasing. Problems still exists in the analysis of biological samples, such as discrete analysis results of the same method between laboratories and systematic errors among the main analysis methods of individual elements. There are technical difficulties in the analysis of some elements. Analysis and testing technology needs to be continuously improved to cope with the characteristics of a special biological sample matrix, low composition content and difficult testing.

BACKGROUND Perlite is a vitreous rock formed by rapid cooling of volcanic eruptive acidic lava. It is a very important non-metallic mineral, because of its brittleness, light weight, rapid expansion on heating, and other excellent characteristics, and is widely used in construction, water treatment, agriculture and other fields. However, according to the International Database for Certified Reference Materials (COMAR), there is no reference material for perlite composition analysis at home and abroad. So, in order to meet the research needs of perlite, it is necessary to develop one. OBJECTIVES To develop a reference material for composition analysis of perlite. The reference material can basically cover the chemical composition needed by the market. METHODS Perlite samples were collected from Shangcheng County, Henan Province. The collected samples were dried and picked out, the bulk ore was crushed and ground in a ball mill for 40h, then the samples were coarse crushed and discharged, and the debris was removed by 1mm sieve. The samples were dried at 105℃ for 24h, dehydrated and inactivated. After drying, the samples were crushed in a grinder containing high-alumina ceramic balls, and the grinding time was determined by the time required to meet the particle size requirements of the first class standard substance. The processed samples were stored temporarily in polyethylene plastic vats under constant temperature and clean conditions, then sub-packed at 70g per bottle for test. Random samples were taken for homogeneity and stability tests. Through nine collaborative laboratories, more targeted valuation methods such as the gravimetric method, volumetric method, inductively coupled plasma-mass spectrometry, and inductively coupled plasma-optical emission spectrometry were used to ensure the accuracy of the perlite valued components. RESULTS Fifteen items of 60 components were tested for uniformity and stability, including Ag, As, B, Ba, Be, Bi, Cd, Co, Cr, Cs, Cu, Ga, Hf, Hg, In, Li, Mo, Nb, Ni, Pb, Rb, Sb, Sc, Sn, Sr, Ta, Th, U, V, W, Zn, Zr, SiO2, Al2O3, TFe2O3, FeO, MgO, CaO, Na2O, K2O, MnO, TiO2, P2O5, LOI, TC, and rare earth elements. The RSD of most of the components was less than 3%, and the F value of the variance test was less than the critical value [F0.05(29, 60)=1.65], indicating that the homogeneity of the reference material was good. During the stability inspection period, there was no significant difference in the content of the 60 components, indicating that the reference material was stable. The data were processed in accordance with General and Statistical Principles for Characterization of Reference Materials and outlier tests were performed using the Grubbs and Dixon methods. According to statistics, there were 2500 original data of perlite reference material, and 68 outliers were eliminated, with an elimination rate of 2.7%. The standard value and uncertainty of the certified reference material for perlite composition analysis were determined by statistical processing of the constant value test data. The normal distribution of the mean data set was tested by the method of Shapiro-wilk, and the test results were all normal distribution. The final values were 63 components, covering major, trace, and all rare earth elements. The contents of three major components MgO, CaO and TFe2O3 were all less than 1%, which formed a gradient with the existing silicate reference material content. CONCLUSIONS The certified reference material for perlite composition analysis developed in this paper has met the requirements of Technical Norm of Primary Reference Material (JJF1006—94) by processing, crushing, homogeneity and stability test of the candidate. The test for uniformity and stability adopts the same detection technology as the fixed value method, and the selected fixed value technology is suitable and accurate, which ensures the accuracy of the fixed value data. The development of perlite composition analysis standard material has enriched the series of China geological mineral composition analysis standard material, and its chemical composition is numerous, it provides important technical support for instrument calibration, analysis method verification, quality control and quantity traceability of modern analytical technology.

Boron (B) is a light and fluid-mobile element. It has two stable isotopes: 10B and 11B. The two isotopes fractionate significantly in nature due their relatively large mass difference. Therefore, B isotopes are one of the non-traditional stable isotope tracers, which have been used in the research areas of chemistry, environmental, bioscience, earth and planetary sciences. In the last twenty years, the analytical methods of B isotopes have been continuously improved and many important advances have been made. However, there are still some challenges to obtaining high-quality B isotope data. The techniques of B isotope analysis are quite different among laboratories, which arise principally from three stages: sample digestion, purification, mass spectrometry.Because B is volatile and isotopic fractionation may be induced by different coordination in different pH environments, sample digestion, and purification have a great impact on the high-precision measurement of B isotopes. Four digestion methods have been applied for extracting B from samples, including pyro-hydrolysis, acid dissolution, alkali fusion, and ashing. Pyro-hydrolysis requiring large volumes of water is time-consuming. Acid dissolution is one of the most popular techniques due to the small volumes of reagents needed and hence lower levels of contamination. Samples are dissolved with different acids such as hydrochloric, nitric, hydrofluoric, and perchloric. Painstaking attention is required with hydrofluoric acid since BF3 is highly volatile and easily lost in nature. Suitable amounts of mannitol are added during acid dissolution to form a stable boron-mannitol complex to prevent the loss of B and avoid B isotope fractionation.Alternatively, alkali fusion is a dissolution method for solid rock samples. High purity fluxing agent is needed, such as K2CO3, Na2CO3, NaOH, NaOH, and Na2O2. As all the B would be present as borate in the resulting alkaline solution, alkali fusion eliminates the risk of B isotope fractionation due to evaporation. The advantage of this method is that it is rapid and relatively large numbers of samples can be processed. The ashing is mainly used to digest plant samples. Ashing was chosen for plant sample decomposition because ashing removes the organics and avoids the use of reagents carrying a B blank or generating isobaric interferences.Once a sample is dissolved, it is necessary to purify B before analysis. There are two principal methods currently in use, which are ion exchange and microsublimation. The ion exchange techniques can be divided into those involved in using B-specific resin Amberlite IRA 743 and those using cation (AG50W-X8/AG50W-X12) or anion (Bio-Rad AG MP-1) cation exchange resins. Microsublimation is an effective and simple method to purify B. It is used to purify B from organic-enriched solutions. Microsublimation appears advantageous in terms of matrix removal efficiency and low procedural blank, however the technical challenges involved are also great.There are two main types of B isotope analytical methods: in-situ and solution methods. Solution methods analyse B ratios using thermal ionization mass spectrometry (TIMS) method or multiple collector inductively coupled plasma-mass spectrometry (MC-ICP-MS). The in-situ method, uses secondary ion mass spectrometry (SIMS) method or laser ablation multiple collector inductively coupled plasma-mass spectrometry (LA-MC-ICP-MS) to measure samples with high B concentration. The accurate and precise determination of the B isotope composition is still a difficult task. For solution methods, the difficulty arises principally from the near ubiquitous level of B contamination in most standard clean laboratories, the light mass of the element, the occurrence of only two stable isotopes, and the large mass difference between them. For in-situ approaches, the difficulty arises principally from a lack of reference materials, surface contamination, limited precision in low-concentration samples, and limitations in reproducibility in high-concentration samples. On the whole, MC-ICP-MS is the dominant method for B isotopic analysis, which is still has the challenges of matrix effect, memory effect, and mass bias.The relevant techniques inherent to the three stages of B isotope analysis are summarized and the advantages and disadvantages of the different techniques are discussed. The aim of the work contained in this paper is to further promote the progress and development of domestic and foreign scholars in the research of B isotope geochemistry.

Fluoride is one of the important trace elements of human life and health. A proper amount of fluoride is beneficial to health. Excessive intake of fluoride will lead to dental fluorosis, bone fluorosis and urolithiasis, and serious excessive intake will affect the human central nervous system, endocrine hormone levels and reproductive system. The same lack of fluorine can also cause dental caries, Kaschin-beck disease signs and osteoporosis symptoms and cause hematopoietic dysfunction. Due to the chemical characteristics of fluorine, the forms of fluorine in the natural environment are very complex, and the transformation between different forms needs further study. How to quickly and accurately determine the content of fluorine in soil, rocks and minerals is of great significance for evaluating regional geochemical behavior and preventing fluorine-related diseases in humans.In this paper, the research progress of fluorine analysis and testing technology in soil, rocks and minerals in recent years is described. The methods, reagents and processes of sample pretreatment are summarized. The matrix correction, interference control, performance and application status of different testing methods are reviewed. In order to ensure the accuracy and reliability of the test results, it is necessary to eliminate the interference of metal cation, matrix effect and particle size validity, select the appropriate pretreatment and detection technology, reduce the detection limit, and constantly improve the accuracy and precision of the test.At present, the commonly used pretreatment methods mainly include pressed powder pellet, fusion, steam distillation, high temperature combustion hydrolysis, alkali fusion and acid dissolution. Among them, the pressed powder pellet method is simple, employs nondestructive analysis, has high sample preparation efficiency, and can meet the requirements of pretreatment of fluorine in large quantities of soil. The fusion method can effectively reduce the particle size effect and mineral effect, but different matrix samples need to use different oxidants, the preparation process is complicated, and requires high experience of the sample maker. Steam distillation and high temperature combustion hydrolysis are mainly used in rock sample treatment. The interference of metal ions can be effectively reduced by steam distillation or high temperature combustion hydrolysis. The test results of the samples treated by the alkali fusion method are stable and widely used, but there is metal ion interference, which leads to low fluorine test results. The acid dissolution method is used mainly for the decomposition of some specific ore samples, such as phosphate ore, and is rarely used at present.The commonly used determination methods include the ion selective electrode method, ion chromatography, XRF method, spectrophotometry, colorimetric method and liquid chromatography. Among them, the ion selective electrode method is mature and widely used because of its high accuracy and good stability. The detection limit of ion chromatography is low, but the test efficiency is low. X-ray fluorescence spectrometry uses lossless injection, simple environmental protection and can measure multiple elements at the same time. The colorimetric method is not accurate enough, the stability of the method is poor, the analysis steps are more complicated, and it is not suitable for the analysis of daily samples. Liquid chromatography is rarely used at present because of the expensive pretreatment equipment.At present, the alkali fusion method (accounting for 26%) is widely used as the most important pretreatment means, but it has many shortcomings, such as large reagent consumption, long process, complicated steps and cationic interference. Further research and practice are needed to optimize testing techniques and methods. The high temperature combustion hydrolysis method (accounting for 13%) and steam distillation method (accounting for 18%) can reduce cationic interference, but their cumbersome steps and special expensive equipment are currently used less. The ion selective electrode method accounted for more than one third of the test methods. Currently, the pre-treatment method using alkali fusion-ion selective electrode method is one of the most effective test technologies for the determination of fluorine content in soil, rocks and minerals.Pressed powder pellet method (accounting for 17%) has potential research value because of its unique non-destructive injection, simple, fast and environmental protection, and the matching XRF method (accounting for 29%) can realize multi-element combined measurement, which has significant advantages in stability and precision. The future research direction of fluorine determination by X-ray fluorescence spectrometry will be how to reduce the detection limit of the method and eliminate the particle size effect and mineral effect. Other analysis and testing techniques are not recommended because of cumbersome procedures, expensive pre-treatment equipment, only certain types of samples can be processed, and limitations of testing methods.As fluorine is a light element and its occurrence forms are complex and diverse, it is necessary to select appropriate analysis and testing techniques according to the characteristics of sample types.The main research directions of fluorine analysis and testing technology in soil, rocks and minerals and pretreatment methods are focused on non-destructive analysis of samples, safety and environmental protection, rapid and other aspects, and the main research directions of testing technology are focused on the establishment of multi-element simultaneous determination. In conclusion, the determination of fluorine in soil, rocks and minerals by pressed powder pellet-X-ray fluorescence spectrometry has important research value.

As a form of new emerging pollutant, antibiotics have been detected in soil, surface water, groundwater, sediment and other different environmental media. As a major country in the production and usage of antibiotics, China's production and usage are increasing year by year. However, most antibiotics used for humans or animals cannot be fully absorbed and metabolized and will enter the environment in the form of prototypes or metabolites through waste and wastewater accumulating in soil and leaching into groundwater. Antibiotics entering the environment may affect microbial ecology, produce resistance genes, and even threaten human health. Compared with surface water, polluted groundwater is hidden, lagging and difficult to recover. The pollution of antibiotics in groundwater, as the main source of drinking water, has attracted much attention.So far, the research on antibiotics in China is still mainly on surface water and soil, and there are few observations on antibiotics in groundwater. In order to systematically grasp the current pollution situation of antibiotics in groundwater in China, relevant literature on antibiotics in groundwater from 2012 to 2021 is reviewed in this paper. Twenty-eight antibiotics detected more than 100 times in environmental media in China were selected as target antibiotics, and the detected concentrations were summarized and analyzed. It was found that the concentrations of 28 antibiotics commonly detected in groundwater varied by more than 4 orders of magnitude, from 0.1ng/L to more than 1000ng/L. The most frequently detected antibiotics were norfloxacin, ofloxacin, sulfamethoxazole, sulfadiazine, enrofloxacin, and erythromycin. Through comparative analysis of the detection of antibiotics in various places, it can be seen that the concentration of antibiotics in groundwater is controlled by the properties of antibiotics, the location of pollution sources, hydrogeological structure and the amount of usage and emissions. From the perspective of spatial distribution, sulfonamide antibiotics are the most detected in northeast China, quinolones are the most detected in North and East China, quinolones and tetracyclines are the most detected in southwest China, and the research on antibiotics in groundwater in northwest China is relatively low. So far, restrained by the detection limits and detection types of the analysis methods, a comprehensive investigation and evaluation of antibiotics in groundwater is not possible.Due to the wide variety of antibiotics, their different structures lead to different physical andchemical properties. They exist in trace concentrations in the complex environment media, which also affects the accuracy of their qualitative and quantitative analysis. Therefore, the establishment of a sensitive and specific multi-component simultaneous analysis method has been a key issue for antibiotics research. The analysis methods of antibiotics are summarized, which are divided into qualitative analysis methods and quantitative analysis methods. The principle, advantages, disadvantages and application range of several antibiotic analytical methods are presented. These methods include microbial inhibition method (MIT), thin layer chromatography (TLC), gas chromatogram-mass spectrometry (GC-MS), high-performance liquid chromatogram-nuclear magnetic resonance (HPLC-NMR) and liquid chromatogram-mass spectrometry (LC-MS). Liquid chromatogram-mass spectrometry (LC-MS) is the most commonly used method for antibiotic analysis because of its high sensitivity, low detection limit and simultaneous determination of multiple antibiotics. With the rapid development of antibiotic analysis methods, some antibiotics in groundwater can be accurately quantified by using HPLC-MS/MS and other technologies. However, the number of antibiotics that can be analyzed and identified at one time is still limited. The research group of authors has established the qualitative spectrum library of common drugs by UPLC-MS/MS. In the future, the types of antibiotics that can be qualitatively identified in the spectrum library can be expanded by adding the mass spectrum information of antibiotics. Under specific conditions, the spectrum library can be used to carry out semi-qualitative identification of antibiotics in groundwater. At present, the commonly used quantitative detection methods include enzyme-linked immunoassay, capillary electrophoresis, and liquid chromatography-mass spectrometry. Compared with the other two methods, liquid chromatography-mass spectrometry has the advantages of high sensitivity, good selectivity and accurate quantitative ability. It is commonly used for the detection of trace antibiotics in reported water samples.Antibiotics exist in the environment at trace levels and the matrix of environmental samples is complex, so the pretreatment process, including antibiotic separation, purification and concentration, often becomes the key step of determination. For example, the samples to be tested should be adjusted to an appropriate pH to enhance the enrichment of target antibiotics on HLB columns, and Na2EDTA should be added to inhibit its complexation with calcium and magnesium and other metal ions in groundwater. The accuracy of antibiotic determination will be improved, and the detection limit will be lowered for water samples by solid phase extraction and the subsequent concentration process. In addition to the detection limit and recovery rate of antibiotics affected by the analytical instrument, the presence states of antibiotics in water samples will also affect the accuracy and precision.Antibiotics may exist in the ionized state, complex state, adsorption state and other forms in groundwater. At different pH values, antibiotics may exist in neutral, cationic, anionic, orzwitterionic forms. When it coexists with metal ions, complexation reaction will occur under certain conditions to form antibiotic-metal complex which will reduce the peak area to a certain extent or cause tailing phenomenon on the reverse analytical column. The formation of the complex may also change the environmental behavior (migration, transformation, toxicity, etc.) and ecological effects of antibiotics. In addition, the analysis of antibiotics in different adsorption states can be used to evaluate the differences in microbial killing effects of different adsorption forms, especially the differences in ARG production and spreading. This will be helpful for accurately evaluating the potential effects on the environment or human beings and effectively controlling the risks of antibiotics in environmental media. Therefore, the existing form analysis of antibiotics is of great significance for the further accurate determination of antibiotics and the evaluation of environmental effects.Up to now, limited by the detection limits and detected types of antibiotics in analytical methods, there has not been a comprehensive national-scale investigation and evaluation of antibiotics in groundwater in China. Only by clarifying the concentration level and spatial distribution of antibiotic pollution in China's groundwater can it help to understand the contents of relevant laws and regulations on new emerging pollutants and support the establishment of a regulatory framework for natural resources and the environment. In conclusion, optimizing qualitative and quantitative detection methods, analyzing different existing forms of antibiotics, comprehensively investigating antibiotics in groundwater, and scientifically evaluating the relationship between antibiotic forms and ecotoxicological effects are the main contents of antibiotics research in groundwater in the future.

Karst landforms are mainly special landscapes formed by carbonate dissolution.They are characterized by calcium abundance, lack of soil resources, and insufficient water resources. The growth and development of vegetation in the karst area is restricted by the bedrock. It is very important to understand the synergistic interaction between vegetation metabolism and geochemistry of carbonate rocks in karst areas to maintain the stability of structure and function of the karst ecosystem.The mechanism and law of interaction between vegetation and rock geochemical background in karst areas from two aspects is expounded in this paper: vegetation community promotes weathering of carbonate rocks and geochemical background restricts vegetation.Through summarizing: (1) Plants promote the weathering and dissolution of carbonate rocks through physicochemical and biological actions, such as secreting carbonic anhydrase organic matter, improving the water retention performance of rock surface through boring by organisms and accelerating the disintegration of broken rocks through root splitting, thus forming a unique karst geochemical background of drought, high calcium, shallow soil layer and lack of nutrients in the soil layer.(2) With the long-term interaction between plants and the karst environment, plants adapt to environmental stress by adjusting their own structures and physiological functions, and even their unique plant succession rules. The plants that survived eventually evolved into unique karst plants that were drought-resistant, adaptable to high-calcium environments, and able to cope with nutrient deficiencies.Due to the solubility of carbonate rocks, the hydrologic system forms a two-layer spatial structure of surface and underground, which makes it difficult to utilize groundwater resources. As a result, the available water resources of local plants are limited, and are prone to drought stress. The drought resistance of plants adapts to the drought or water shortage environment mainly through physiological and biochemical processes, morphological structure and water use. In the morphological structure of the plant, through the stomatal regulation and the xeric structural characteristics of the leaves, the transpiration water loss of the plant is minimized. Some karst plants can cope with drought stress through physiological and biochemical processes, which can reduce the damage caused by drought stress by increasing the activities of antioxidant enzymes and accumulating osmoregulatory substances through phytochemicals. Karst plants improve water use efficiency and reduce transpiration through different water use methods in the dry season. For example, some plants absorb deep soil, deep bedrock water or groundwater water through developed deep roots, and some plants even use fog water.The adaptability of plants to high calcium is realized through physiological structure and process. In a high calcium environment, karst plants can limit the excess calcium transfer upward by forming calcified roots and keeping the calcium content in plants in a relatively stable state through the regulation of calcium oxalate crystal cells and leaves. Plants can also control the intracellular calcium ion concentration by regulating the calcium pool in vivo and controlling the absorption and transport of calcium.Organic acids and mycorrhiza secreted by roots can help vegetation obtain nutrients in the soil to cope with nutrient deficiency in the soil. The organic acid content secreted by the roots of karst plants is usually higher than that of non-karst plants, and the increase of organic acid content can help plants to absorb trace elements. Arbuscular mycorrhizal fungi (AM) and ectomycorrhizal fungi (ECM) help plants adapt to nutrient deficiency by absorbing mineral nutrients from the soil.(3) The vegetation succession in the karst area is similar to the general stage of vegetation succession in normal landforms, but the vegetation succession in the karst area has the particularity of self-generation. The vegetation succession from the middle to the top of the mountain takes a longer time. Vegetation succession changed physical and chemical properties and soil quality. In the process of succession, soil bulk density gradually decreases, and porosity gradually increases over time. At the same time, soil nutrients accumulate with the positive succession of vegetation. During the positive succession process of karst vegetation, the soil water and fertilizer retention capacity is enhanced, the stability is increased, and the survival probability of species and the species diversity are also increased. The special rock geochemical background in the karst area leads to the obvious changes in the spatial distribution of soil resources. High soil heterogeneity promotes the formation of plant community species diversity. For example, the tropical karst area in Xishuangbanna, Yunnan Province covers an area of 3600km2, accounting for 19% of the land area. The forest survey results in the karst area show that there are 153 families, 640 genera and 1394 species of vascular plants, accounting for 77.7% of the total floristic families, 56.1% of the genera and 37.9% of the species, respectively.The karst plant community is the result of the long interaction between the plant and the environment, the continuous adaptation to the environment and the growth and reproduction. The karstification of plants, the adaptation mechanism of plants under the typical karst soil environment such as drought, high calcium stress and lack of nutrient elements, as well as the succession characteristics of karst vegetation shown in the adaptation process and the biodiversity of vegetation are a whole interaction. The site growth of vegetation promotes the weathering of carbonate rocks and the formation of soil, creating conditions for their own growth. Meanwhile, soil area and soil thickness are positively correlated with plant diversity. The succession of vegetation changes the physical and chemical properties of soil and improves the quality of soil, and the karstification of carbonate rocks promotes the growth of vegetation. The adaptive mechanism of vegetation affects the distribution and growth of plants and promotes the succession process of plant communities and the formation of plant diversity. Due to the spatial heterogeneity of the karst environment and the diversity of plant habitats, plant diversity in karst areas is manifested as few genera, few species and endemic species. However, the internal relationship between plant diversity and the stability of the community ecosystem, as well as the comparative characteristics with non-karst areas still need to be further studied and explored.

Knowledge of element partitioning in the Earth's interior is of great importance, as it can contribute to interpret fundamental geological problems, such as element cycling, ore formation, and the property of supercritical fluid. The concentration and partition coefficients of elements under high temperature and high pressure could be in situ extracted by Diamond Anvil Cell (DAC) combined with Synchrotron Radiation Micro X-ray Fluorescence Spectrometry (SR-μXRF) with high accuracy and high resolution. The element's speciation in various phases could be simulated theoretically, based on geochemical thermodynamics, which helps to reveal the mechanism of element partitioning. The in situ detecting methods of element partitioning under high temperature and high pressure by DAC combined with SR-μXRF and geochemical thermodynamics simulation, and their applications on migration of elements in the Earth's interior, ore formation, the early development of Earth's formation and so on, are summarized in this paper. Studying element partitioning behavior under high temperature and high pressure using the proposed method will become more complex, which needs higher requirements for the temperature and pressure conditions. From this paper, the aim is to update and enrich the element partition data under high temperature and high pressure, which will enhance the understanding of material cycling in the Earth's interior.

Bromine exists mainly as ions in bromide brine and halide sulfate brine in the hydrosphere of the crust. Powder carrier pellet method is commonly used in analyzing bromine in brine by Wavelength Dispersive X-ray Fluorescence Spectrometry (WDXRF). However, this sample preparation method has the disadvantages of large work load, sample inhomogeneity and outer contamination, which affects the analytical accuracy. Samples were pretreated by film adsorption, and film material and sample weight were optimized and are reported in this paper. Firstly, 50 μL of brine is dropped to the center of a chromatography filter paper (Ф=40 mm), air dried, and then flattened by high pressure to prepare the film sample for WDXRF test. A standard curve of Br was calibrated by self-prepared standard solution. Experimental results show that the impact of coexisting ions such as K+, Na+, Ca2+, Mg2+, Cl- and SO42- on the detection of Br is negligible. The detection limit of this method is 0.95 mg/L, the precision is less than 0.8% (n=11), and the recoveries are 99.4%-101.2%. The new sample preparation method is very economical and easy to operate, avoiding the use of chemical reagent.

Atomic absorption spectrometry (AAS) was applied to the determination of gold in ores with high grade gold, effectively avoiding the problems caused by the fire assay gravimetric and volumetric method with forcyanide quinone, such as the large amount of toxic chemical reagents required and limits of measurement conditions. Foam enrichment-Flame Atomic Absorption Spectrometry (FAAS) can determine the grade of gold reached up to 500 μg/g in gold ore, but this method adds the filter residue separation, diluted and foam ashing, redissolving process based on the conventional FAAS method. Due to the increase in time of the operation process, the analysis efficiency is not high with increasing probability of error. In this paper, a fast analysis method for high grade gold ore is described. The gold ore sample was dissolved by aqua regia, followed by filtering of the residue. The filtrate with constant volume without preconcentration and separation was determined with FAAS. The precision of the method (RSD) is 1.6%, which is an improvement on the precision of FAAS itself and meets the monitoring requirements of rapid analysis for high grade gold ore samples. The gold ore sample collected from Heilongjiang province (a production monitoring samples), an inspection gold ore sample and a national standard gold ore sample were selected to study the established method in this paper, foam adsorption-FAAS method, cyanide quinone capacity method and fire assay gravimetric method. The results show that the accuracy of the iron content directly affects the high grade gold determination. When the gold sample size was 50-110 μg/g, 110-164 μg/g and 164-218 μg/g, the amount of iron content allowed in the samples was no more than 10%, 20% and 25%, respectively. Based on these studies, this presented method is suitable for gold ore samples with more than 50 μg/g gold and less than 10% Fe. The average content of iron in the earth's crust is 5.63%, and the iron content of most national standard reference gold ore materials are close to the average value. The iron content in general gold ores are rarely at a higher level. Therefore, this method is highly suitable. Compared with the method of foam adsorption-FAAS, the operation processes of foam adsorption-ashing-redissolving were eliminated, which greatly improved the analysis efficiency.

Atomic absorption spectrometry (AAS) was applied to the determination of gold in ores with high grade gold, effectively avoiding the problems caused by the fire assay gravimetric and volumetric method with forcyanide quinone, such as the large amount of toxic chemical reagents required and limits of measurement conditions. Foam enrichment-Flame Atomic Absorption Spectrometry (FAAS) can determine the grade of gold reached up to 500 μg/g in gold ore, but this method adds the filter residue separation, diluted and foam ashing, redissolving process based on the conventional FAAS method. Due to the increase in time of the operation process, the analysis efficiency is not high with increasing probability of error. In this paper, a fast analysis method for high grade gold ore is described. The gold ore sample was dissolved by aqua regia, followed by filtering of the residue. The filtrate with constant volume without preconcentration and separation was determined with FAAS. The precision of the method (RSD) is 1.6%, which is an improvement on the precision of FAAS itself and meets the monitoring requirements of rapid analysis for high grade gold ore samples. The gold ore sample collected from Heilongjiang province (a production monitoring samples), an inspection gold ore sample and a national standard gold ore sample were selected to study the established method in this paper, foam adsorption-FAAS method, cyanide quinone capacity method and fire assay gravimetric method. The results show that the accuracy of the iron content directly affects the high grade gold determination. When the gold sample size was 50-110 μg/g, 110-164 μg/g and 164-218 μg/g, the amount of iron content allowed in the samples was no more than 10%, 20% and 25%, respectively. Based on these studies, this presented method is suitable for gold ore samples with more than 50 μg/g gold and less than 10% Fe. The average content of iron in the earth's crust is 5.63%, and the iron content of most national standard reference gold ore materials are close to the average value. The iron content in general gold ores are rarely at a higher level. Therefore, this method is highly suitable. Compared with the method of foam adsorption-FAAS, the operation processes of foam adsorption-ashing-redissolving were eliminated, which greatly improved the analysis efficiency.

There are broad application prospects for evaluation of measurement uncertainty in the environmental test laboratory based on quality control data accumulated in long-term routine analysis. The quality control charting method is used only for the same concentration data. Linear calibration using reference materials can be used in different concentration measurement data but the complete quality control data cover different concentrations with the same number of measurements and should be prepared before the mathematical mode is established, which makes its application in most testing laboratories unsuitable. Robust statistics is a type of statistical analysis method where it is unnecessary to identify and delete outliers but it can also reduce the effect of outliers on the final results based on all measurement data. Quality control charting methods and robust statistics (iteration method), when outliers exist, are used to calculate intermediate precision (sR′) after normalizing different concentration data by recovery rate and are described in this paper. Five sets of data collected in our laboratory and 19 sets of data from the other laboratories, which cover routine testing items in environmental protection field, were used to verify the feasibility of the new method. It can be shown that the average difference of relative intermediate precision (ΔsR′-rsd) between robust statistics and quality control charting methods are almost in agreement (i.e. 0.15%) for the single concentration data. For the multi-level concentration data after normalization, the average difference (ΔsR′-rsd) between quality control charting and linear calibration, between robust statistics and linear calibration, are 0.43% and 0.20%, respectively. The average of difference (ΔsR′-rsd) between robust statistics and quality control charting method is 0.26%, which indicates that the results of all three methods are generally in line with each other. The principle of the new methods proposed in this paper is easy to understand and the calculation procedure is significantly simplified, making it suitable for cases of linear calibration using reference materials with direct proportion mode.

There are broad application prospects for evaluation of measurement uncertainty in the environmental test laboratory based on quality control data accumulated in long-term routine analysis. The quality control charting method is used only for the same concentration data. Linear calibration using reference materials can be used in different concentration measurement data but the complete quality control data cover different concentrations with the same number of measurements and should be prepared before the mathematical mode is established, which makes its application in most testing laboratories unsuitable. Robust statistics is a type of statistical analysis method where it is unnecessary to identify and delete outliers but it can also reduce the effect of outliers on the final results based on all measurement data. Quality control charting methods and robust statistics (iteration method), when outliers exist, are used to calculate intermediate precision (sR′) after normalizing different concentration data by recovery rate and are described in this paper. Five sets of data collected in our laboratory and 19 sets of data from the other laboratories, which cover routine testing items in environmental protection field, were used to verify the feasibility of the new method. It can be shown that the average difference of relative intermediate precision (ΔsR′-rsd) between robust statistics and quality control charting methods are almost in agreement (i.e. 0.15%) for the single concentration data. For the multi-level concentration data after normalization, the average difference (ΔsR′-rsd) between quality control charting and linear calibration, between robust statistics and linear calibration, are 0.43% and 0.20%, respectively. The average of difference (ΔsR′-rsd) between robust statistics and quality control charting method is 0.26%, which indicates that the results of all three methods are generally in line with each other. The principle of the new methods proposed in this paper is easy to understand and the calculation procedure is significantly simplified, making it suitable for cases of linear calibration using reference materials with direct proportion mode.

Chromite analysis is dominated by chemical analysis, which is a wel-established but complicated procedure. Chromite can also be analysed by X-ray Fluorescence Spectrometry (XRF), however, a high-dilution fusion is not conducive to low content elements. In this paper, a method is reported for the determination of multi-elements (Cr, Si, Al, TFe, Mg, Ca and Mn) in chromite by Wavelength Dispersive X-ray Fluorescence Spectrometry with a low-dilution fusion for Li2B4O7 and LiBO2-mixed flux (20:1 reagent to sample). Also discussed in this paper is the effective flux of molten chromite. The working curve was established by a variety of chromite standard substances and manual preparation of standard materials. The inter-element effect was corrected by using the theoretical alpha coefficient with Compton scattered radiation. The results are consistent with the certified values and RSD (n=10) range from 0.2% to 5.3%. The detection limit of Mn is 60 μg/g. The detection limit of Mn by this method is as low as 225 μg/g which is lower than the previous reported limit of 250 μg/g reported elsewhere. By selecting the effective flux and low dilution ratio, the problem of chromite sample preparation has been solved, which reduces the amount of flux, increases the sample weight, improves the analysis accuracy for low content elements and reduces the cost of analysis.

Matrix interference and co-existent elemental interference are the two key factors necessary to obtain accurate analysis results for Rare earth elements (REEs) in geological samples using the traditional methods. Since Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) is widely conducted in the field of trace element analysis, accurate results of REEs are obtained under optimized conditions. This method was established using ICP-MS to determine 15 REEs and is detailed in this paper. The samples were digested in sealed containers with HCl, HNO3 and HF at high temperature. The solutions were set into a constant volume. Internal standard solutions of 103Rh, 115In and 185Re were on-line loaded into the sample solution during the measurement. The recovery rates are 95%-104% and the RSDs are less than 3.5%. REEs in 24 representative ore samples from 12 countries were analyzed and are reported in this paper. The results show that importing iron ores are LREEs enrichment type. Currently, imported fine ores are mostly combined with different iron ores from multi productive areas. This provides a technical reference for the comprehensive utilization of rare earth elements in iron ore and pollution control and also provides valuable information on the origin of the iron ore.

Polarized Energy Dispersive X-ray Fluorescence Spectrometer is used as a common analytical method for exploration and prospecting on-site, but it constraints the on-site analysis of the high salinity geological or ore sample, for the serious matrix effects and insufficient calibration sample with matrix matching and affects the accuracy of the analysis results, even returning incorrect results. A method is presented in this paper for on-site analysis of Cu, Pb and Zn in polymetallic ores in Qimantage area, Qinghai province. The method is based on a vehicle-loaded Polarized Energy Dispersive X-ray Fluorescence Spectrometry (PE-EDXRF) with solution preparation of samples. Calibrations were conducted by utilizing standard solutions. Compton scattering intensities of Mo Kα from the secondary target were used as the internal standard to compensate for the matrix effect. The precision of the method was examined by on-site analyzing two geological samples from the local mine. Two kinds of double cabin sample cups with acid absorbent and double supporting films were developed to prevent the spectrometer from damage by the possible leakage and evaporation of the acidic sample solution. Two different procedures of ore sample digestion were tested on site and are described in this paper. The relative standard deviations (RSD, n=10) were in the range of 1.08% to 2.13%, when samples were pretreated by the second procedure. The accuracy and reliability of the method were tested by on-site analyzing of 4 quality control samples from Application Center for Geological Test of Qinghai Province and 13 geological samples from the local mine. When samples were pretreated using the second procedure, relative errors less than 5.0% were obtained for the 4 quality control samples with the element concentration higher than 0.5%. For the 13 local mine samples, PE-EDXRF results were compared with Atomic Absorption Spectroscopy (AAS) ones, the obtained correlation coefficients for Cu, Pb and Zn were 0.9984, 0.9986, 0.9997 respectively, and the corresponding linear regression equations were wAAS(Cu)＝0.9882×wPE-EDXRF+0.0213, wAAS(Pb)=1.0365 0.1265，wPE-EDXRF-0.1265, wAAS(Zn)=1.0250×wPE-EDXRF+0.0186. When the concentration of Cu was 0.75%-8.57%, Pb was 0.78%-29.1%, Zn was 0.11%-2.51%, average relative deviations of Cu, Pb and Zn, between PE-EDXRF results and AAS ones of the 13 local mine samples were 2.87%, 2.82% and 6.84%. We conclude that the vehicle-loaded PE-EDXRF coupled with the double cabin sample cups and the second procedure offers a satisfactory solution for high precision on-site polymetallic ore sample analysis. The above work is to expand the capability of PE-EDXRF on-site analysis to various metal ore matrix samples and is a supplement to the already established powder sample preparation method.

BACKGROUND Water quality security and human health are important to ensure rural revitalization of old liberated areas. The continuous development and utilization of ion-adsorption type REE deposits in northern Ganzhou aggravate trace elements from ores and tailings to the water cycle, thereby endangering the sanitation and safety of drinking water. OBJECTIVES To investigate and evaluate health risk and water quality on the watershed scale of rare earth ore concentration area in the Huangpi River Basin. METHODS The contents of manganese, cadmium and other elements were determined by inductively coupled plasma-optical emission spectrometry/mass spectrometry(ICP-OES/MS). By choosing "standards for drinking water quality" (GB 5749—2006) as the evaluation basis, the water quality index (WQI), hazard quotient (HQ), and cancer risk (CR)were adopted to evaluate water quality and human health risks through analyzing 9 indices including Pb and Mn. RESULTS NH3-N and Mn were anomaly indices whether in surface water or groundwater. The average values of NH3-N were 750μg/L and 4533μg/L in surface water and groundwater, respectively. Index values of Mn were 207μg/L and 4009μg/L in surface water and groundwater, respectively. Arsenic, class I carcinogen published by the World Health Organization, had no abnormality in surface water and groundwater. Moreover, 85.7% of surface water and groundwater was found to be suitable for drinking upon analyzing the WQI values. The HQ average value of NH3-N was less than 1 in surface water and groundwater so it had no harmful effects on human health. However, the HQ average value of Mn was more than 1, which may be harmful to human health. CR values of As varying from 10-6 to 10-4 were also calculated, and the risk of cancer was acceptable. CONCLUSIONS It is suggested that relevant departments should pay attention to the status of NH3-N and heavy metal elements in water during the reclamation evaluation of rare earth mines. The research detailed in this paper confirms that the groundwater monitoring system of manganese should be improved.

A description of the synthetic experiment of methane hydrate is given in this paper, along with a preliminary study of ion concentration changes during the process, whilst providing important technical support for the gas hydrate geochemical exploration. In this article, the development of a set of experimental devices, which simulate the formation process of methane hydrate, is also discussed in this paper. The position and shape of hydrate, the reaction time, the temperature and pressure of the experiments were observed during methane hydrate formation. The concentrations of major ions including K+, Na+, Ca2+, Mg2+, Cl-, SO42- were continuously detected during the process to investigate the relationship among the major ion concentrations, temperature and pressure. The results show that methane hydrate forms randomly in seawater. It may have a different nucleation and agglomeration process of hydrate under the same initial conditions. There was a good positive linear relationship between the ions variation and methane gas consumption in the system with the correlation coefficients between 0.9848 to 0.9950, which was not affected by the formation position and morphology of the hydrate. The ion content had small differences under the same gas consumption in the microenvironment of the methane hydrate formation process. These important features provide the basis to make a preliminary estimate of gas consumption by using the major ion content in pore water around the methane hydrate.

The developments of in-situ X-ray Fluorescence (XRF) analysis techniques in the fields of Portable XRF Spectrometer, in-situ analytical methods and its applications are described in this paper. Portable XRF Spectrometer has been divided into four generations, based on the aspects of X-ray excitation sources, X-ray detectors and electrical circuit units. The paper also documents some in-situ analytical methodologies for analyzing X-ray spectra, overcoming the influence of the matrix effect, unevenness effect, moisture effect and heterogeneous effect on in-situ XRF analysis results. Finally, some applications in mineral exploration, environmental investigation, cultural relic discrimination and alloy analysis are introduced. The domestic Portable XRF Spectrometer was between generations Ⅲ and Ⅳ. The low power miniature X-ray generator and electric refrigeration semiconductor detector were dependent upon importation from foreign countries. The full digital X-ray energy spectrum collector is not yet available commercially. It is also pointed out that there are some capabilities for improving the accuracy and method detection limit of in-situ analysis. Research fields need be broadened to include the applications of Portable XRF Spectrometer.

The consumption of raw ore and ore concentrate and the product of tailings are currently very high in China. The hazardous and toxic contaminants released from mineral products have become a general environmental problem. In this paper the components of contaminants in mineral products and recent research involving them is briefly introduced. The four different leaching simulation experiments of humidity cell, column, static immersion and extraction are discussed in this paper. The humidity cell experiment can simulate natural weathering reactions of products and determine the dissolution rates of contaminants and related products. The column experiment can simulate hydrometeor or drench conditions to provide the kinetic basis for both adsorption and desorption. The static immersion experiment can simulate immersion processing in water, in order to study the release law and related products. The extraction experiment can be used to conduct chemical morphological analysis for contaminants to evaluate the mobility and stability of contaminants in a medium. Various impact factors for contamination dissolution are summarized. Influencing factors in order of strong to weak were pH, leaching or soaking time, temperature, and solid-liquid ratio and ore particle size. In most cases, the higher the pH, the longer leaching or soaking time, the higher the temperature, the smaller solid-to-liquid ratio and the smaller the mineral products particle size, the easier to leach contaminants. Leaching of contaminants was found to be a long-term and latent process. There was a series of physical and chemical reactions that took place inside the products, which indicated the different leaching rules with the diffusion effect. At present, the object of this study is mainly focused on tailings, however, the leached contaminants from the stacked raw ore and ore concentrate products for human use need further research. Leached contaminants need to be predicted and assessed in order to take effective measures to control or manage pollution from mineral ores.

The quality of regional geochemical survey samples is currently estimated indirectly by internal and external laboratory quality control. The method described here effectively improves the quality of geochemical samples. However, the improvement of the method is limited when the contents of the actual samples and external quality control samples have large differences. Since most elements are in accord with a normal distribution in a regional geochemical survey sample, a comparison was made between the real and standard normal distribution of the elements, which passed the normal distribution test and gave an estimate of the quality by using a comparison of the real and standard graph′s superposition using SPSS and Excel software. This method was directly applied to estimate the quality of analysis data for geochemical survey samples in Jiangxi province. The result of the normal distribution test indicated that the analysis data of the trace elements need a logarithmic conversion before the normal distribution can be studied. The quality evaluation method in this paper was not suitable for Ti, W and Cr etc in this area. The overlap ratios of 18 elements such as Co, Hg and Ga were more than 0.9. The overlap ratios of CaO and Na2O were less than 0.9. The results of the actual samples indicated that the detection limits need to be reduced in order to improve the analysis qualities of CaO and Na2O. It was a valuable attempt to directly evaluate the quality of analysis data for regional geochemical survey samples by using the method reported in this paper, which was a reference and supplement for the current methods of quality evaluation.

BACKGROUND Standard mode with interference correction or kinetic energy discrimination mode is commonly used for the determination of trace silver in geochemical samples by inductively coupled plasma-mass spectrometry (ICP-MS). Interference of both stable isotopes of silver occurs in the mass spectrum of the oxides or hydroxides of zirconium and niobium. Moreover, for samples with a higher content of interfering elements and a lower content of silver, the determination accuracy is low, requiring separation of the interfering element from silver in the solution. OBJECTIVES To develop a method for the determination of trace Ag in geochemical samples. METHODS Common sample digestion methods and chemical separation (ion exchange separation) were introduced in detail and were discussed in this paper. RESULTS As proved by first grade standard materials, the result was consistent with standard recommended values, with the relative standard deviation of 4.3%-12.1% (n=12). The detection limit (3SD) of the method was 0.0072μg/g. CONCLUSIONS This method is suitable for the determination of trace silver in soil, stream sediment and rock samples. The introduction of phosphoric acid does not affect the determination of other conventional elements, and the same digestion solution can be used to determine Ag and other elements.

BACKGROUND In the past twenty years, methods for metal isotopes analysis (iron, copper, zinc, magnesium, calcium, lithium, molybdenum, selenium, mercury, chromium, cadmium, alum, barium, titanium, etc.) have been established. The sample pretreatment during metal isotope analysis includes two processes: the digestion of the sample; and the separation and purification of the analyzed elements. In order to ensure the accuracy and precision of metal isotopes data, two general principles of sample treatment must be followed. Elements that may interfere with the isotope analysis of the analyzed elements should not be introduced into the analysis. The analyzed elements should not be lost during the experiment. OBJECTIVES In order to understand the pretreatment methods for metal isotope analysis. METHODS Common sample digestion methods and chemical separation (ion exchange separation) were introduced in detail and were discussed in this paper. RESULTS The common sample digestion method for metal isotope analysis is the acid dissolution method (Teflon bombs and microwave digestion). The separation and purification of the element to be measured mainly uses the ion exchange separation method. The same resin can be used for the chemical separation of different elements, and the same element can also be chemically separated by using different resins. The matrices of different types of samples are quite different, and different processes are required to separate the analyzed elements. The separation requirements of different samples can be met by changing the separation process of the predecessors, including changing the resin or the amount, changing the eluent or the amount, and increasing the separation steps. CONCLUSIONS Based on the authors' experience, details should be paid attention to during treatments for metal isotope analysis: (1) HClO4 must be thoroughly removed at high temperature during sample digestion, because its strong oxidization can destroy the effectiveness of resins; (2) when the same volume of resin is put into the column, the thinner the column is, the slower the flow rate of the eluent, and the later elution of the elements to be measured; (3) the smaller the volume of the eluent added each time, the better the separation effect during ion exchange purification.

BACKGROUND Inductively coupled plasma-mass spectrometry (ICP-MS) has been widely used in the determination of trace elements in carbonate rocks. Due to the low Ni (1.6-50.5μg/g) and Sc (0.3-6μg/g) in carbonate rocks, the signal values are obviously interfered by high CaO (up to 56%) and MgO (up to 21%) during ICP-MS determination, resulting in the test value much higher than the true value. OBJECTIVES To solve the problem of non-mass spectrum interference and mass spectrum interference of Ni and Sc during ICP-MS analysis of carbonate rocks and use appropriate correction method. METHODS The single standard series of Ca and Mg and national first-level reference materials of carbonate rocks were used to study the interference of high content of Ca and Mg on Ni and Sc in the carbonate during ICP-MS analysis. Testing of the single standard series was aim to explore ways of interference on Ni and Sc by high content of Ca and Mg in solution. The national first-level reference material of carbonate rock was further selected as the calibration carrier to eliminate the matrix effect of Mg. At the same time, according to the good linear relationship between the content of CaO in the sample solution and the interference degree of Ni and Sc, the interference equations of CaO and △Ni and △Sc were fitted respectively, and used for interference deduction of Ni and Sc in several national first-level reference materials and unknown samples of carbonate rocks. The accurate test values of Ni and Sc in carbonate rocks by ICP-MS were obtained. RESULTS It was found that the high content of Mg had a non-mass spectrometric interference matrix effect on the analysis of Ni and Sc. High content of Ca forms oxides, hydroxides and polyatomic ions, resulting in mass spectrometric interference on Ni and Sc. The degree of interference had a good linear relationship with the Ca content in the solution. Compared with a single standard to perform interference correction on actual samples, this method used national first-level standard materials as the calibration carrier, which overcomed the interference of matrix effects. Verified by GBW07108 and other five national primary standard materials of carbonate rocks, test values agreed with the standard values, with a relative standard deviation (RSD, n=10) of less than 5.5%. Correction results of the unknown carbonate samples were compared with the results of the inductively coupled plasma-optical emission spectroscopy (ICP-OES) and the X-ray fluorescence spectrometer (XRF), respectively, the relative deviation was less than 15%. CONCLUSIONS The correction method proposed in this paper has solved the mass spectral interference and non-mass spectral interference in ICP-MS analysis of Ni and Sc in carbonate rocks. The method is simple and feasible, and the results are accurate and reliable.

BACKGROUND Cadmium is a volatile element with chalcophile affinity. In the marine environment, Cd is a micronutrient element, while in the ecological environment and agricultural soil environment, Cd is a toxic element. Therefore, Cd isotopes have been used in marine science, earth science, environmental science, and agricultural scientific research, and show great application potential. OBJECTIVES To summarize the high-precision analytical technology and applications of Cd isotopes in different research fields. METHODS The recent research progress in digestion methods, separation and purification of Cd, and double-spikes calibration methods for organic matter-rich environmental samples, plant samples and biological samples were summarized. RESULTS For organic matter-rich samples including environmental, plant and biological samples, microwave digestion, high-pressure ashing and perchloric acid digestion can eliminate the influence of organic matter in Cd isotope analysis. Combined AG MP-1(M) resin with hydrochloric acid leaching system can effectively separate the matrix and interfering elements, which will not result in Cd isotope fractionation. The precision of Cd isotope with 111Cd-113Cd isotope double-spike correction was around 0.1εCd/amu. The application of Cd isotopes in marine science, geoscience, environmental science, and agricultural science were also summarized in this paper. Cadmium isotopes were used successfully for building marine biological geochemistry cycles, inversion of ancient marine environments and primary productivity change. In sulfide deposits, Cd isotopes were used to trace the evolution of ore fluids and the source of ore metals, and to discriminate different deposit types. In environmental systems, Cd isotopes were applied to distinguish Cd pollution sources, and to investigate Cd sources, migration, circulation and storage mechanisms in agricultural sciences. CONCLUSIONS The research of the high-precision Cd isotope analytical method and Cd isotope fractionation mechanism and model, will promote to establishment the tracer system of Cd isotope biogeochemistry fractionation and innovative development of non-traditional stable isotope geochemistry.

BACKGROUND Under the background of coordinated development of resources, environment and economy, the development of green mining has become a national strategic focus and has been widely recognized. Environmental investigation and evaluation is one of the main content in investigation and assessment of large lithium metallic mineral bases in Sichuan Province, which will play an important role in solving the bottleneck problems, such as prospecting deployment and environmental protection in the ecologically fragile district of the Western Sichuan Plateau. OBJECTIVES To put forward the green investigation method and to establish an index system of environmental evaluation and demonstration of typical mining areas. METHODS Green investigation and environmental assessment were combined, an indicator framework in four levels was constructed, and the status quo and change information of the ecological environment through 3S technology were extracted. Based on three years of surface water, soil and other multi-environmental media field survey and analysis data, a mature evaluation method has been optimized, and a large-scale lithium resource base environment evaluation model based on support vector machine was established by using a more compatible and scalable Python language programming. RESULTS Using this model, the current status of large-scale bases was divided into four categories:environmentally poor areas, general environmental areas, better environmental areas, and good environmental areas. The overall accuracy rate was 97.77%. CONCLUSIONS The set of a targeted evaluation index system established and reported on in this paper effectively evaluates the environmental status of large-scale lithium resource bases in Western Sichuan, and realizes the visual level of 'pixel-level' environmental status of large-scale lithium resource bases through technological innovation. The method objectively reflects the development and environmental impacts of the Jiajika mining area and surrounding resources, and to a certain extent, can assist in regulating the management and decision-making of the development and utilization of large-scale mineral resources.

BACKGROUND Over the years, the total anomaly analysis results of geochemical exploration have found that there are not many deposits. Under the conditions of epigenetic conditions, different elements have different migration and deposition laws and primitive occurrence states. The geochemical analysis gives the full analysis of the elements cannot accurately reflect the mineralization anomalies situation. Therefore, the existence form and existence state of the elements are crucial for judging whether it is a metallogenic anomaly. OBJECTIVES This paper establishes the phase analysis method of molybdenum in geochemical soil samples from the characteristics of Heilongjiang geological landscape. METHODS The phase states of molybdenum are divided into five phases:water extraction phase, weak organic binding phase, oxide binding phase, Fe-binding phase, and residue phase. The detection limits of molybdenum phases determined by ICP-MS are:water extraction phase 0.0011μg/g, weak organic binding phase 0.020μg/g, oxide binding phase 0.100μg/g, Fe-binding phase 0.100μg/g, the residue phase is 0.100μg/g. RESULTS The method was used to analyze the samples with molybdenum anomaly in a certain part of Heilongjiang Province. The results showed that molybdenum was mainly composed of Fe-binding phase, which belonged to the vein type and conformed to one of the types of molybdenum deposits. CONCLUSIONS The method improves the accuracy of prospecting using geochemical anomalies.

BACKGROUND The Sichuan Jiajika ore field is one of the most concentrated areas of lithium resources in China and even in the world. At present, the understanding of the spectroscopy of the Jiajika lithium deposit is still very poor. OBJECTIVES To better understand the spectra of lithium ore deposits and provide the basis for hyperspectral study of lithium ore deposits by spectrum measurement of typical rocks. METHODS Spectra of typical rocks and minerals collected in Jiajika area were measured by Analytical Spectral Devices (ASD) FieldSpec-4 Spectroradiometer and a spectral library of this area was built. The spectral characteristics of rocks and minerals including biotite schist, grenatiteschist, grenatite cordieriteschist, hornstone, granite, pegmatite containing spodumene, pegmatite without spodumene, quartz vein, feldspar, spodumenemono, biotite, aquamarine were analyzed. RESULTS The results indicate that there are differences in spectral characteristics between rock masses and surrounding rocks. The reflectance of surrounding rocks is less than 0.2, and absorption characteristics are not obvious, whereas the reflectance of rock masses is less than 0.5, and there are three absorption features at 1413 nm, 1911 nm, 2197 nm. In addition, granite, pegmatite containing spodumene, and pegmatite without spodumene can be discriminated by their unique spectra on 1413 nm and 2197 nm. The unique spectral characteristics of spodumene and aquamarine can be applied for ore exploration. CONCLUSIONS The research on the surface spectroscopy of the Jiajika type lithium ore deposit carried out in this paper has important guiding significance for hyperspectral remote sensing mapping and geological prospecting.

BACKGROUND The analysis of six indices (pH, total alkalinity, chloride ion, calcium ion, magnesium ion and sulfate radical) in underground water needed to be sampled separately for each index. The steps were tedious with low efficiency. Furthermore, the total alkalinity, chlorine ion, calcium ion, magnesium ion and sulfate radical usually used manual visual titration, resulting in manual operation error, poor precision, and inaccuracy. OBJECTIVES To establish an accurate and rapid method for the analysis of six indices in underground water. METHODS The method established and described in this paper only needed two samples and the Automatic Potentiometric Titrator could determine the end point automatically. The Automatic Potentiometric Titrator could accurately control the addition of standard solution to 0.1 μL, and eliminate mutual interference by adjusting the detection order, acidity and the addition of a masking agent. RESULTS The recoveries of this method are 93.5%-120.0%, and the relative standard deviations (RSDs, n=10) are 0.18%-11.33%. CONCLUSIONS The results obtained by potentiometric titration had better parallelism and stability, especially when the measured water samples were more turbid or colored.

BACKGROUND In geological studies, Sr and Nd isotopes are classical isotopic dating and tracer systems. OBJECTIVES The traditional separation method usually uses the AG50W-X8 resin to elute and separate Sr and REEs in sediments, and then uses Sr-special resin and Ln-special resin to purify Sr and Nd, respectively. However, this method has lower recovery of REEs (only 50%) for sediments with high Fe content. METHODS In addition, height and elution acid species of AG50W-X8 resin, Sr resin elution acid volume, and Ln resin washing ways have impacts on the separation of Sr and Nd. In this work, in order to investigate the effect of these factors on the separation of Sr and Nd in detail, we took river sediment (GBW07309) as an example. RESULTS The results showed that (1) high Fe content significantly affected the separation effect of Sr and Nd, and AG1-X8 resin could effectively remove Fe; (2) using 1 mL AG50W-X8 resin and HNO3 as the eluting acid, the separation effect of Sr and REEs was the best; (3) Sr and Rb could be effectively separated when the elution acid volume of Sr-special resin reaches 15 mL; (4) Nd was separated well without trailing phenomenon when gravity column method was used to wash the Ln-special resin. CONCLUSIONS This method solves the Fe interference during separation of Sr and Nd. More than 99% of K, Na, Ca, Mg, Fe, Rb, and Sm were removed, which fully satisfied the requirements for the analysis of Sr and Nd isotopes. This paper provides more detailed empirical data for the separation of Sr and Nd isotopes in sediments by ion exchange resin method.

Acidolysis hydrocarbon is an important index with relatively high accuracy in the geochemical exploration for oil and gas and has been widely used. Detailed study of acid-hydrolyzed gases can help further explain its mechanism and help develop new analytical indicators. The content of acidolysis hydrocarbons and other gas released by hydrochloric acid in the samples from geochemical exploration for oil and gas by Gas Chromatography have been determined, and are presented in this paper. There is a positive correlation between the contents of methane and non hydrocarbon gas. The elements and mineral composition of the sample were measured by X-ray Fluorescence Spectrometry (XRF) and X-ray Diffraction (XRD), respectively, whereas the gas-liquid inclusion composition was analyzed by Laser Raman Spectroscopy after sample smashing. The conclusions are as follows:(1) The content of methane and hydrogen in the acidolysis hydrocarbons is independent of the elemental composition of the sample and is positively related to the carbonate minerals. The contents of methane and hydrogen can reflect the situation of deep oil and gas. (2) Two kinds of gas do not exist in the form of physical adsorption but in the smaller space. It is proved that the analysis method of acid hydrolysis hydrocarbon has high stability. (3) There is direct evidence that two kinds of gases exist in the inclusions at the same time, which infers that two types of gases have the same source. Due to the correlation between methane and hydrogen, the content of hydrogen from acidolysis hydrocarbons will be a new analysis index in the geochemical exploration for oil and gas.

The thickness of the methane hydrate stable zone is mainly controlled by the stability of methane hydrate. The temperature, pressure, pore water salinity, and gas component affect the thickness of the hydrate stable zone. The formation of methane hydrate is closely related to the formation of water. Various salt ions in formation water (Cl-, Na+, Mg2+, SO42-, Ca2+, and transition metals Fe, Mn, Cu, Co, Ni) can affect the formation and decomposition conditions of natural gas hydrate. Therefore, studying the effect of salts on the stability of methane hydrates is helpful to better understand the reservoir-forming conditions of methane hydrate. The effects of chloride, sulfate and carbonate on the stability of methane hydrate are evaluated in this paper. With the increase of salinity, the phase equilibrium curve of methane hydrate migrates to low temperature and high pressure under the same salinity condition. The inhibitory effects of different salts and anion and cation on methane hydrate are summarized. Under conditions of the same concentration and different types of salts, when the concentration of salt ranges from 1 to 1.5 mol/L, the inhibition effect of salt on methane hydrate is MgCl2 > CaCl2 > NaCl > KCl. When the concentration of salt is larger than 1.5 mol/L, the inhibitory effect of CaCl2 on methane hydrate is stronger. The inhibitory effect of anions on methane hydrate is controversial, and the inhibitory effect of Mg2+ on methane hydrate is the strongest. From available research results, there is still a gap between the existing data and the actual geological conditions. It is necessary to strengthen the detailed study on chloride-sulfate-carbonate-methane-water systems under actual experimental conditions. It is proposed that the combination of the high-voltage visual reaction chamber with Micro Laser Raman Spectroscopy is likely to accurately obtain the stable temperature and pressure conditions of gas hydrate formation, clarify the inhibitory effect of cations and anions, and understand how salts and ion affect the formation of hydrate and its stability, which will provide reference for the future exploration and development of hydrate.

At present, sulfur in soil is mainly determined by X-ray Fluorescence Spectrometry and tube furnace combustion iodine methods. The analysis speed of these two methods is slow, and the analysis accuracy is poor for both high and low content samples, difficult to meet the requirements of accurate and rapid determination of many samples. In order to improve the speed and accuracy of analysis, a new method for the determination of sulfur in soil samples by Inductively Coupled Plasma-Optical Emission Spectrometry combined with four acids digestion was developed. In this paper the digestion effect of aqua regia, aqua hot water bath and HCl-HNO3-HF-HClO4 is compared. The four acids digestion method was proven to better dissolve sulfur in soil samples. The method is simple, rapid and accurate with a low detection limit of 10 μg/g, analysis range between 33.3 μg/g and 50000 μg/g, and relative standard deviation between 0.47% and 4.05%. Many elements such as potassium, sodium, calcium, magnesium, iron, manganese, beryllium, lithium, lanthanum, cerium, scandium, vanadium, cobalt, nickel, and titanium can be determined simultaneously in a solution without increasing analysis cost. The method, which has been verified with actual samples, is suitable for application in the geological industry.

Helium is an indispensable and rare strategic element. A method of sampling the top helium gas in the helium gas resource investigation was used, and is described in this paper. Thermal conductivity detector (TCD) of the Gas Chromatograph was used to detect helium gas. The helium gas standard was used to study the helium gas storage container, the storage medium, the storage temperature, and the storage time. Results show that the glass jar, the saturated salt water, the low temperature, and the inverted storage are the best methods to save the head space gas. At room temperature, the helium head space gas storage period is about 2 months, whereas under refrigerated conditions (4℃), the storage time reaches 3 months. Therefore, the author suggests that the helium head space gas collection method is as follows. The fresh soil samples are collected in a 500 mL glass bottle, and then are injected into the saturated salt water. A 50 mL space remains in the bottle, and then the bottle is sealed by silica gel and kept inverted. For the helium top gas stored under normal temperature and refrigerated conditions, the test should be completed within the corresponding storage period to ensure the accuracy of the test data.

The identification and classification of marble depended mainly on the identification of rock slices and the semi-quantitative detection of minerals by X-ray Diffraction (XRD). It was found that the results of identification of rock slices were not always consistent with those of the semi-quantitative detection by XRD. Therefore, it is necessary to introduce other techniques to verify the results of thin section observation and XRD semi-quantitative analysis. 32 marble samples were analyzed by X-ray Fluorescence Spectrometer, the results and finding of which are reported in this paper. Based on the chemical composition of rock, rock impurity, magnesite, and calcareous coefficients are used to classify the marble. The results show that magnesite coefficients of calcite marble, dolomite marble, and magnesite marble are 0.01-0.13, 0.40-0.46 and 0.97-0.98, respectively. Calcareous coefficients are 0.78-0.84, 0.30-0.49 and 0.01-0.02, respectively. Different types of marble have various magnesia and calcareous coefficients, which can be used as the main basis for the division of marble types. Only the contents of SiO2+Al2O3 in rocks are less than 30% (impurity coefficient less than 1.00), then can be classified as marbles. The establishment and application of impurity, magnesia and calcareous coefficients in marble can be used to correct the inconsistent results between thin section observation and X-ray Powder Diffraction mineral semi-quantitative analysis, making marble classification more accurate.

Carbon and nitrogen isotopes are essential tools to study paleoclimate, palaeoenvironment, and ecosystem. At present, carbon and nitrogen isotopes are commonly determined by Elemental Analyzer-Isotope Ratio Mass Spectrometer (EA-IRMS). Reaction temperature and sampling weight directly affect the burning of samples, and thus affect analytical precision. Using EA-IRMS technology and taking standard samples as references, the carbon and nitrogen isotope values were determined at different conversion temperatures to study the optimum reaction temperature, in order to ensure the accuracy of the analysis presented in this paper. At the same time, by analyzing the detection limits of samples with different nitrogen contents, the relationship between the nitrogen content of the sample and the lowest detection limit was determined and thus the lowest quantity of samples for accurate determination of nitrogen isotopes were also defined. The results show that reaction temperature has a significant effect on analytical precision. Analytical precision of carbon isotope is less than ±0.2‰ when the reaction temperature is either 900℃ or higher than 900℃, but the precision of nitrogen isotope can reach ±0.3‰ only when the reaction temperature is no lower than 950℃. The linear relationship between nitrogen content and detection limit was expressed as R2=0.873 according to the data. According to this relationship, the sample introduction quantity can be determined and controlled when analyzing nitrogen isotope.

The Ningxia Helan Stone is one of the well-known stones that are used for making inkslab in China. The development and application of Helan Stone is becoming more and more widespread, and therefore, it is necessary to carry out a systematic study. At present, there are only preliminary artificial experiments and systematic study of mineralogy is lacking. The conventional gemological test method is combined with spectroscopic analytical methods such as optical thin section identification, X-ray Fluorescence Spectrometry (XRF), X-ray Powder Diffraction (XRD) to study the gemological characteristics, chemical components, rock structure, and the mineral compositions of the Ningxia Helan Stone and is reported in this paper. The results show that the minerals of the Ningxia Helan Stone include major hydromica and sericite, and minor ferric oxide, sandy clastics, chlorite, and trace amounts of hematite, rutile, and tourmaline. The Ningxia Helan Stone has chemical components including SiO2, Al2O3, TFe2O3, K2O, MgO, TiO2, CaO, P2O5, a refractive index of 1.56-1.57, a density of 2.81-2.86 g/cm3, and a mohs hardness of 3-4. The main color-causing factor of the Ningxia Helan Stone is also discussed. Based on the correlation between the morphology and content of Fe element and the color of the Helan stone, it is considered that Fe is the main color-causing element. The most characteristic parameters of Ningxia Helan Stone have been determined in this study, which provides technical support for follow-up accurate nomenclature and identification method for the Helan Stone.

As strategic emerging mineral resources supported by the state, niobium and tantalum are the functional and structural materials needed for the development of emerging industries. Therefore, conducting research on the determination of niobium and tantalum in related materials is of great significance. Unfortunately, niobium and tantalum have similar physical and chemical properties, making it difficult to separate them. However, they are easy to hydrate. Geological samples are difficult to be decomposed, thus the determination of niobium and tantalum has always been a difficult issue. Sample pre-treatment technology and modern analytical techniques are reviewed in this paper. Sample pre-treatment is the key step for niobium and tantalum analysis, therefore a suitable sample digestion and preconcentration method combined with analytical methods and sample characteristics is the premise of accurate determination of niobium and tantalum. Instrument analysis is the mainstream of modern analytical technology. Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) are the most widely used methods for the determination of niobium and tantalum, but it is necessary to solve problems such as coexisting component interference, matrix effects and salt influence. Laser Ablation (LA), X-ray Fluorescence Spectrometry (XRF), and Neutron Activation Analysis (NAA) are the development direction of tantalum and niobium analysis, due to the fact that they avoid the complicated sample pre-treatment and addition of impurities by solid sample introduction.

At present, the solid phase extraction packing of organic ligand/nano inorganic composite material is used to separate and enrich metal ions, which has become a hot research topic in analytical chemistry. A novel nano-TiO2/TSC solid-phase extraction packing was prepared by grafting thiosemicarbazone containing N, S coordination atoms onto the surface of nano-TiO2 by condensation reaction and is described in this paper. The structures and the property of synthesized composite were characterized and analyzed by Infrared Spectroscopy, X-ray Diffraction Scanning, X-ray Photoelectron Spectroscopy, and Electron Microscopy. The composition and size distribution of the packing particle were more uniform (the particle size is 200-300 nm) and more stable than the solid phase extraction packing made by physical blending technology. The saturation adsorption capacities of Sb3+, Cd2+ and Ba2+ on the solid phase extraction column prepared by this method at 30℃ were 13.9 mg/g, 12.9 mg/g, and 11.2 mg/g, respectively. The recoveries of three metal ions were 97.94%, 95.65% and 94.04%, respectively under the optimal experimental conditions. The data has good reproducibility with RSD < 5.5%. Thus, the adsorption property of the new nanometer TiO2/TSC composite solid phase extraction packing is an improvement on the styrene-methyl acrolein-thiosemicarbazide coated nano-titanium dioxide packing and nano-titanium dioxide packing. The contents of Sb3+, Cd2+ and Ba2+ in water samples were determined by Inductively Coupled Plasma-Mass Spectrometry coupled with the TiO2/TSC composite solid phase extraction packing, which yields detection limits of 0.061 μg/L, 0.013 μg/L, and 0.075 μg/L for Sb3+, Cd2+ and Ba2+, respectively.

Acid-modified natural magnetite shows excellent arsenic removal properties due to its change in specific surface area and internal structure. It is essential to study further its adsorption to arsenic in water, in order to provide data for practical engineering applications. The feature of arsenic adsorption by modified magnetite immersed in 0.5 mol/L hydrochloric acid and ignited for 10 minutes at 150℃, and the construction of its adsorption rate curve chart is described in this paper. Results of the experiment on adsorption influencing factors indicate that when initial pH value are 6-9, magnetite shows strong adsorption property. Ions such as Cl-, Ca2+, Mg2+, HCO3-, CO32- do not have competitive adsorption with As(Ⅲ) and As(Ⅴ), but PO43-, NO3-, and SO42- have competitive adsorption with As(Ⅲ), in the order of PO43->SO42- >NO3-. PO43- and NO3- have competitive adsorption with As(Ⅴ). In combination with XRD, SEM, and other research results, preliminarily studies show the arsenic removal mechanism of modified magnetite, and conclude that modified magnetite shows an obviously increased specific surface area and that Fe(Ⅱ) and Fe(Ⅲ) contained in its surface products are the main cause for improving arsenic adsorption ability. Experimental results demonstrate that modified natural magnetite is a de-arsenic material for water, which deserves further study and practical application.

Tourmaline is an efficient tracer during diagenesis and metallogenesis. Chemical composition of tourmaline can not only be used to give information about environment of diagenesis and metallogenesis, but can also be useful in prospecting. Prospecting work of pegmatite-type rare metal deposits in Southern and Western China has seen a big breakthrough, however, there has been no obvious advance in prospecting in Northern China. Therefore, it is necessary to carry out systematical and detailed prospecting work. There are a lot of grey black idiomorphic tourmalines in pegmatite veins in Quyang County, Hebei Province, which makes it suitable for carrying out systematical mineralogy research. Samples based on detailed field work were systematically collected and are described in this paper. Microscopic identification, Powder X-ray Diffraction and Electron Microprobe were used to determine the chemical composition of tourmaline, in order to investigate the types, and diagenetic and metallogenic environment of tourmaline. Electronic Probe and Powder X-ray Diffraction show that tourmaline in Zhongzuo pegmatite belongs to dravite but is close to that of schorl. The Ca-Fe-Mg ternary diagram indicates that the diagenetic environment is poor Ca metamorphic pelite, metamorphic arenite and quartz-tourmaline rock. The chemical composition of tourmaline is closely related to the types of surrounding rock. The dravite in pegmatite veins was formed by assimilation blending between magmatic melt and surrounding rock at a temperature of 700-600℃ where Mg and Fe in surrounding rock provide the necessary sources for the formation of tourmaline. The systematical study of chemical composition of tourmaline in Zhongzuo pegmatite veins provides fundamental geological data and a prospecting direction for pegmatite-type deposits.

The Zhaojinggou Nb-Ta polymetallic deposit in Inner Mongolia is a newly discovered large rare metal ore deposit. The reserve of Nb-Ta oxides is more than 8200 tons. Previous studyfocus on geological features of this deposit, but they the precise mineralization age remains unknown. In this paper, muscovite in amazonite granite pegmatite was used to constrain the timing of mineralization using 40Ar-39Ar isotope method. Results show that Nb-Ta mineralization is mainly hosted in alkali-feldspar granite, alkali-feldspar aplite, greisen, and amazonite granite pegmatite. According to the geologicalrelationship between Nb-Ta minerals and muscovite, we can infer that Nb-Ta minerals and muscovite are formed at the same time. Thus, the muscovite plateau ages of 123.57±0.66 Ma and 124.0±2.0 Ma can represent the mineralization age. Results show that the Zhaojinggou Nb-Ta polymetallic deposit was formed at late Yanshanian (or at least Early Cretaceous), the 40Ar-39Ar age have bigger difference with the zircon age, which is of great importance for ore genesis. Combining with regional geology, the author thinks that an essential rare-metal mineralization happened in the middle part of inner Mongolian axis on the north margin of north china platform during the late Yanshan movement.

Internationally, two advanced nondestructive methods of drill core testing include hyperspectral technology and XRF scanning technology. Both methods include problems that the higher the accuracy requirements, the higher the accuracy of the complete core data, the less accurate data of the incomplete core and rock specimen, and the difficulty of satisfying fast and accurate requirements of small sampling areas of the geological samples. Portable X-ray Fluorescence Spectrometry (P-XRF) was used for the study described in this paper. The weighted average of the multi-point test method reduces the influence of complex sample lithology and mineral species and improves the accuracy of this method. Compared with quantitative analysis, the results with a semi-quantitative range indicator role are more than 82%. The weighted average is nearly 22% higher than the arithmetic mean, and thus the accuracy of the multi-point test is improved significantly. Furthermore, the method can be used to analyze more elements after the rough processing of specimens, which better solves the sampling problem of specimens in the geological cores and samples library. Through this pre-research, it is found that silver content is higher in some specimens of lead-zinc mine and Mo content is 0.3% in the 168.46-171.24 m position of drilling core Zk0901. This study provides important prospecting information for the reuse of the specimens in the geological cores and samples library.

Economic development requires exploration and exploitation of mineral resources. It is difficult to find surface outcrop deposits, which will cause soil pollution by heavy metals that is a severe hazard to the environment and human health. Microorganisms in nature interact with heavy metals in air. Microorganisms with this specificity can be applied to metal prospect exploration and environmental bioremediation of heavy metal pollution. Interaction mechanisms between specific microorganisms and heavy metals and its application to exploration and environmental bioremediation of heavy metal pollution have been reviewed. The focus of this paper is on the adsorption, accumulation and transformation process between specific microorganisms and heavy metal ions, as well as the mechanism of microbial organisms changing heavy metal distribution, occurrence and toxicity. The interaction mechanism between Bacillus cereus and gold and its application potential to find concealed gold deposits were reviewed. Removal of heavy metals in the soil by the specific microorganism through the adsorption of metabolites and assisting plants to repair heavy metal pollution were introduced and elaborated upon.

X-ray Fluorescence Spectrometry (XRF) can be used to rapidly determine the total content of barium in barite. However, the barium carbonate included in the total barium will result in inaccurate results of barium sulfate. Moreover, copper, lead, zinc and other non-ferrous metal elements can damage the sample melting pot. Acid treatment is required to remove interference such as barium carbonate and lead. The residue ratio of the different samples after the acid treatment is different to before and the ratio of the flux to sample is uncertain, and thus the content of barium sulfate cannot be accurately determined. Therefore, it is essential to ensure that the melting agent has the same proportion as the sample. The sample pretreatment conditions, melting conditions and equipment conditions were optimized and are described in this paper. 10% hydrochloric acid mixed with 10% nitric acid was used to dissolve the sample. The sample solution was filtered to remove barium carbonate, calcium sulfate and copper, lead, zinc and other non-ferrous metal elements. Alumina oxide was added to undissolved samples after 700℃ calcination to reach the original sample weight, which attains the same proportion of flux and sample. Ammonium nitrate was used as the oxidant, and lithium bromide and ammonium iodide were used as demoulding agents. Samples were melted at 1075℃, and barium sulfate content in the barite was determined by XRF. The relative standard deviation (RSD) of the method is less than 0.4% and the detection limit is 72 μg/g. This method needs less detection time and suffers from less interference elements than determination by Inductively Coupled Plasma-Optical Emission Spectrometry, improving the test efficiency and analysis quality.