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Pd nanoparticles were generated over Al2O3 modified by cellulose allowing a facile crystallization and used for CO oxidation. Smaller particles were prone to be formed over the support with the assistance of cellulose. The enhanced catalytic activity could be ascribed to the positive interaction between Pd particles and the modulated support. [ABSTRACT FROM AUTHOR]

Uranium resource distribution and accurate reserve evaluation are important references for mineral investment and production. Eight kinds of interpolation methods in the Groundwater Modeling System (GMS), including ordinary kriging (OK), are used in this study to predict the spatial distribution of reserve-related parameters, such as uranium grade, ore thickness and uranium content per square meter. The present study draws the following conclusions: (1) Cross-validation found that the uranium grade value using the spherical method is the closest to the actual value. The spherical method has the best interpolation effect. (2) The relative error, which is +3.62%, between the uranium reserves that is calculated by the spherical interpolation method and that by the traditional calculation value is the smallest. (3) The setting of the number of interpolation grids is related to the actual number of boreholes. The ratio between the two will affect the accuracy of reserve estimation, and different interpolation methods have different degrees of influence on reserve estimation. This method is applicable to all in-situ leaching sandstone uranium mines. Further study needs to be carried out toward heterogeneity of three-dimensional space, which will make the estimation more accurate. [ABSTRACT FROM AUTHOR]

What Is Already Known About This Topic?: Acrylamide (AA) is toxic and potentially carcinogenic and could be formed during the cooking process. It is understood that almost all foods cooked at high temperature contain AA, especially fried foods. The exposure of AA in food threatens human health., What Is Added by This Report?: In the Sixth China Total Diet Study (TDS), AA was detected in 73.3% samples of the 12 food categories with the concentrations ranging from undetected to 176.90 μg/kg. The average dietary intake of AA was 0.175 µg/kg body weight per day and a significant decrease (45.1%) was observed compared with the Fifth China TDS. Among the 12 food categories, vegetables (59.0%), cereals (18.9%), and potatoes (10.1%) were the main contributors to AA exposure at 88.0%., What Are the Implications for Public Health Practice?: This study highlighted the need to continuously monitor dietary acrylamide exposure in China, including changing food processing methods and making reasonable selection of foodstuffs in the daily diet., Competing Interests: No conflicts of interest., (Copyright and License information: Editorial Office of CCDCW, Chinese Center for Disease Control and Prevention 2022.)

Obejective: To develop a method for the determination of 13 antibiotics in 8 classes for desinfection products by ulta-high perfomance chromatography-tandem mass spectrometry(UPLC-MS/MS)., Methods: Samples were extracted by methanol or acetonitrile. The target compouds were separated on a Waters HSS T3 column(100 mm×2. 1 mm, 1. 8 μm), and detected by triple quadrupole tandem mass spectrometer., Results: The 13 selected antibiotics showed good linear relationships in the range of 4-100 μg/L and the correlation coefficients(r~2) were all above 0. 991. The limits of detection ranged from 2 to 25 μg/kg. The recovery rates at three spiked levels(low, medium and high) in three dosage forms of disinfection products were in the range of 71. 2%-130. 4%, and the relative standard deviations(RSD) were all less than 11. 3%, which could meet the detection requirements of illegal addition of antibiotics in disinfection products. Ofloxacin at a concentration of 21. 1 mg/kg was found in a cream disinfection product by the developed method, and no related drugs were detected in other samples., Conclusion: This method is simple, reliable, reproducible, which covers a wide range of antibiotics, and provides technical support for monitoring the illegal addition of antibiotics in disinfection products.

The widespread use of pharmaceutical and personal care products (PPCPs), including antipyretic and analgesic drugs, in the last two decades had led to the existence of PPCP residues in the environment, thus raising concerns about their pseudo-persistent nature and potential threat to human health. Generally, most of the detected contaminants are present at low levels (ranging from ng/L to μg/L) in environmental water. Therefore, advanced analytical methodologies are crucial to monitor the occurrence and distribution of antipyretic and analgesic drugs in environmental water. However, trace analysis of environmental pollutants is always challenging because it is necessary to extract analytes present in the sample at ultralow levels from complex environmental matrices. Therefore, an appropriate sample pretreatment is necessary to enrich the target compounds. Conventional solid-phase extraction materials show poor efficiency for the enrichment of antipyretic and analgesic drugs. We herein report a hydrophilic and lipophilic amphiphilic porous polymeric material GCHM (Guochuang hydrophilic material). GCHM was successfully prepared by a stepwise emulsification and micellization process using N -vinyl-2-pyrrolidone (NVP) and divinylbenzene (DVB) as raw materials. An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the determination of four antipyretic and analgesic drugs in water using our solid-phase extraction (SPE) column. The water samples were extracted and purified by the GCHM solid-phase extraction column, and then analyzed by UPLC-MS/MS. Gradient elution was carried out with 0.1% formic acid aqueous solution and acetonitrile as the mobile phase. The target analytes were separated on an ACQUITY UPLC HSS T3 column (100 mm×2.1 mm, 1.8 μm), and multiple reaction monitoring (MRM) was conducted in the positive electrospray ionization mode. The isotope internal standard method was used for quantitative correction. Comparison of the enrichment efficiencies of Oasis HLB, Bond Elut Plexa, and GCHM revealed that GCHM showed the best performance. Different pH values affecting the enrichment efficiency of the GCHM SPE column were optimized, and the matrix effect was evaluated. The results showed that the four target analytes gave the best enrichment effect on the SPE column at pH 7, and the matrix effect for each substance was between 82.8% and 102.2%, indicating obvious matrix removal after the water sample was purified by the GCHM SPE column. Good correlation coefficients ( r ) greater than 0.995 were observed for all the target compounds in the range of 1-100 μg/L. The method limits of quantitation ( S/N =10) ranged from 1 ng/L to 5 ng/L. The corrected recoveries were 85.6% to 106.4%, and the relative standard deviations (RSD) were under 5.6%. The GCHM solid-phase extraction column is inexpensive and efficient, being suitable for the detection of the four antipyretic and analgesic drugs in water. Subsequently, the occurrence of these selected antipyretic and analgesic drugs in water samples from Shanghai, Jiangsu, and Guangdong provinces were studied. The GCHM column has potential advantages over the commercial imported SPE column and is worthy of widespread application. This column can also aid the enrichment and purification of other compounds with similar structures or properties in water.

Objective: To develop a simple, fast and sensitive analytical method based on isotope dilution-headspace gas chromatography-mass spectrometry for the determination of 1, 4-dioxane residue in the aerosol cosmetics., Methods: Sample was successive weighed and dissolved in 1, 3-dimehyl-2-imidazolidinone(DMI)solvent and isotope internal standard was added. Then transfered to a 20 mL headspace vial. The headspace vial was sealed and extracted 15 min by ultrasonic-assisted extraction. After separated by HP-5 MS fused silica capillary column(30 m×25 mm, 0. 25 μm), the compound was analyzed by gas chromatography-mass spectrometry in selected ion monitoring mode(GC-MS-SIM) and quantified by internal standard method., Results: There were good linear correlations with R~2 no less than 0. 999 in the range of 1. 0-100 mg/kg. The limit of detection(LOD) of this method was 0. 3 mg/kg. At 0. 3, 1. 0, 5. 0 and 30 mg/kg four added concentration, recovery for five kinds of aerosol cosmetic were all between 91. 4% and 104. 2%. The relative standard deviations(RSDs) were 1. 5%-6. 3% and 1. 7%-6. 4%(n=6), respectively., Conclusion: The developed method has proved convenient, time-saving, accurate and sensitive and suited for determination 1, 4-dioxane in aerosol cosmetic.

A method was developed for the screening and detection of food poisonings by ultra high performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry (UHPLC-Q-TOF MS). After extracted by acetonitrile and cleaned-up by QuEChERS, the extract was separated on a Waters Acquity UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm) with the gradient elution of 0.1% (v/v) formic acid in water and 0.1% (v/v) formic acid in acetonitrile. TOF-MS scan-information dependent acquisition (IDA)-product ion scan was performed in positive electrospray ionization (ESI) mode to acquire high resolution MS and MS/MS spectra in one injection, and rapidly screen 581 target compounds by SCIEX OS software, including 546 pesticides, 24 mycotoxins, 11 rodenticides. The target compounds were qualitatively confirmed by mass accuracy of precursor, isotope distribution of precursor, fragment ions of precursor, and library search. Carbofuran was detected in 9 out of 11 samples with the proposed method. The retention time was further confirmed by the standard of carbofuran. The results showed the retention times were coincident between the samples and reference standard, and the deviations of accurate mass numbers were all less than 3.7×10 -6 . The scope of the relationship was good and the correlation coefficient was 0.998. The instrumental limit of detection ( S/N =3) was 0.3 μg/kg, and the limit of quantification ( S/N =10) was 1 μg/kg. The recoveries at 10, 50, 200 μg/kg levels were 75.6%-95.9%, and the RSDs ( n =6) were 3.6%-6.9%. The method is rapid, simple, accurate and sensitive. It is suitable for the rapid screening and detection of public safety incidents.

Objective: To establish a method for simultaneously determining the urinary concentrations of 8 carbamate pesticides., Methods: After being purified by acetonitrile precipitation, urine samples were transferred to a liquid chromatography-tandem mass spectrometry system, and the concentrations of 8 carbamate pesticides were determined by external standard method. A C18 column was used for ultra-high-performance liquid chromatography; methanol/ammonium acetate solution was used as the mobile phase for gradient elution; the mass spectrometer was operated in a multi-reaction monitoring mode., Results: The calibration curves were linear when the urinary concentrations of these carbamate pesticides were 20~800 µg/L, and the recovery rates were 61.0%~121% at spiked levels of 20, 200 and 800 µg/L, with a relative standard deviation of 1.7%~5.5%., Conclusion: This determination method meets the Guide for establishing occupational health standards-part 5: Determination methods of chemicals in biological materials, and can be used for simultaneous determination of 8 carbamate pesticides in the urine of poisoning patients.

Objective: To establish a method for simultaneously determining the urinary concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG), trans, trans-muconic acid (tt-MA), and S-phenylmercapturic acid (S-PMA) in subjects exposed to benzene., Methods: After being purified by a solid-phase extraction column, the urine samples were transferred to a liquid chromatography-mass spectrometry system, and the concentrations of 8-OHdG, tt-MA, and S-PMA were determined by external standard method. A C18 reversed-phase column was used as the chromatographic column, and methanol/acidic ammonium formate solution was used as the mobile phase for gradient elution. The mass spectrometer was operated in a multi-reaction monitoring mode., Results: For tt-MA, the calibration curves were linear in the range of 10-1000 µg/L, and the recovery rates were over 90% (relative standard deviation (RSD) < 3%) at spiked levels of 50 µg/L and 500 µg/L. For S-PMA and 8-OHdG, the calibration curves were linear in the range of 1-100 µg/L, and the recovery rates were over 85% (RSD < 5%) at spiked levels of 5 µg/L and 50 µg/L., Conclusion: This determination method meets the requirement of Biological materials-, Methods: of monitoring-Guide of development (WS/T 68-1996) and can be used for simultaneous determination of 8-OHdG, tt-MA, and S-PMA in urine.

A rapid method for the simultaneous screening and detection of 20 illegally added anti-diabetic chemical components in hypoglycemic and weight-reducing health foods was developed by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). After extracted by methanol, the sample was separated on a Poroshell 120 EC C18 column (100 mm x 2.1 mm, 2.7 microm) with the gradient elution of 5 mmol/L ammonium acetate and acetonitrile as mobile phases. The electrospray ionization (ESI) source in positive or negative ion mode was used for multiple reaction monitoring (MRM) mode. The 20 illegally added chemical components showed good linear relationships with the correlation coefficients more than 0.99. The recoveries were in the range of 75.9% - 114.0%, and the relative standard deviations (RSDs) were all not more than 11.3%. The limits of detection (LODs) were all in the range of 0.3 - 1.5 microg/L. This method is rapid, simple, sensitive, accurate and of good specificity for cracking down illegally added anti-diabetic chemical components.

A method for the simultaneous determination of 34 pesticides in rice, proso millet and wheat by QuEChERS coupled with on line gel permeation chromatography-gas chromatography-mass spectrometry (GPC-GC-MS) was developed. The effects of the sample weight, extraction solvent, sorbent for purification were investigated. The matrix effect and the usefulness of analyte protectant were also studied. The identification and quantification were performed by GPC-GC-MS in selected ion monitoring (SIM) mode and exrternal standard method. The calibration curves of the 34 pesticides showed good linearity in th range of 0.0125-0.2 mg/L with thea correlations coefficients (r2) between 0.968 and 0.999. The average recoveries were 94.5%-117.1%, 83.1%-121.7% and 93.1%-120.2% with the relative standard deviations (RSDs, n = 6) no more than 14.5%, 15.1% and 15.2% in rice, proso millet and wheat samples, respectively. The LODs of this method were 0.0281-5.31, 0.0282-4.82 and 0.0273 -5.13 microg/kg (S/N = 3) for rice, proso millet and wheat samples, respectively. The low cost and less consumption of reagents of this method are in accordance with the concept of green chemistry. The convenient operation and versatility of this method are suitable for the fast screening and detection of the 34 pesticide residues in rice, proso millet and wheat.

An analytical method using HPLC-MS/MS was developed for qualitative and quantitative analysis of 23 sedative drugs in health foods. The method was based on the sonication-assisted extraction of the health food samples using 10 mL methanol. The extract was then isolated by centrifugation and the supernatant was separated on an Agilent Eclipse Plus C, column with gradient elution at a flow rate of 300 microL/min. A binary mobile phase was 10 mmol/L ammonium formate (solvent A) and acetonitrile/methanol (1:1, v/v; solvent B). The electrospray ionization (ESI) source in positive ion mode or negative ion mode was used for multiple reaction monitoring (MRM). The external standard method was used for the quantification. The calibration graphs were linear in their concentration ranges with the correlation coefficients more than 0. 990. The limits of detection (LOD, S/N= 3) were between 0. 02 - 1.0 microg/L. The recoveries for all the drugs in health foods were 82. 3% - 114. 8% with the relative standard deviations less than 14. 1% at three spiked levels. Thirteen kinds of health foods were tested, in which meprobamate and oxazepan were found in one sample separately, and zaleplon was found in two samples. The method is specific, sensitive, easy and quick and suitable for the confirmation and quantification of the 23 sedative drugs in health foods.

A rapid method for the simultaneous screening and detection of ten anticoagulant rodenticides in foods was developed by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). After the extraction by acetonitrile and clean-up by QuEChERS, the extract was separated on a Poroshell 120 EC-C18 column (100 mm x 2.1 mm, 2.7 microm) with the gradient elution of 5 mmol/L ammonium acetate and acetonitrile. The detection was carried out by UPLC-MS/MS using a negative electrospray ionization interface in multiple reaction monitoring (MRM) mode. The ten anticoagulant rodenticides showed a good linear relationship (r > 0.99) in the range of 5 - 500 microg/L. In the four samples of chili sauce, flour, vinegar and soy sauce, the spiked recoveries were in the range of 72.6% - 112%, and the relative standard deviations (RSD) were all not more than 11.2%. The limits of detection (LOD) were all in the range of 0.5 - 4.5 microg/kg. This method is rapid, simple, sensitive, accurate and of good specificity for the satisfactory rapid screening and detection of the ten anticoagulant rodenticides in the sudden public health security events.

Background: Abelmoschus esculentus L. is a healthy vegetable belonging to the family Malvaceae. This article reports the contents of total phenolics (TP) and total flavonoids (TF) in 80% methanol extracts of the flower (FL), fruit (FR), leaf (L), and seed (S) of A. esculentus, and in 0, 10, 30, 50, and 70% methanol eluates (ME), through the HP-20 column chromatography of 80% of the methanol fruit extract after it is defatted with petroleum and extracted with ethyl acetate. All the names of the samples are shortened for AEE-FL, AEE-FR, AEE-L, AEE-S and 0% MEF-WE, 10% MEF-WE, 30% MEF-WE, 50% MEF-WE, 70% MEF-WE respectively. In addition, the effects of the aforementioned extracts on 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging and on ferric reducing antioxidant power (FRAP) have been evaluated., Materials and Methods: The antioxidant activity of the extracts and the enrichment fraction of A. esculentus were also evaluated by two assays, the DPPH radical-scavenging and ferric reducing antioxidant power (FRAP). The content measurement of TF and TP adopts the UV-2102 PCS method, and the measurement of the antioxidant activity adopts the Infinite M 200 method., Results: The experiment results show that all the different parts and different enrichment fractions of the water extracts of A. esculentus contain phenolics and flavonoids. Through the research of antioxidant activity we know that all the parts of the methanol extracts and different enrichment fractions of water extracts in the A. esculentus have the effect of scavenging free radicals, among which the antioxidant activity in the 50% MEF-WE part is the strongest. Here, the main components of antioxidant activity must be the flavonoids and phenolics, and furthermore, we know that there is a direct relationship between the contents of flavonoids and phenolics and the antioxidant activity., Conclusion: The study suggests that A. esculentus may be the potential rich source of natural antioxidant. The experiment result provided a scientific basis for the further research and development of A. esculentus.

A method for the analysis of common antibiotics and metronidazole in cosmetics was developed by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS). One gram of each cosmetic sample was extracted by methanol-water containing 0.1 mol/L formic acid (1:1, v/v). The extracted sample was filtered before being analyzed with UPLC/MS/MS. The effects of formic acid concentration in the mobile phase on the sensitivity and retention time were studied, and the results showed that 1% was the optimum concentration. Seven analytes, minocycline, oxytetracycline, tetracycline, chlortetracycline, doxycycline, chloramphenicol, metronidazole, can be separated and detected in 5 min, which is much faster than that by the conventional liquid chromatography. The detection limits were 3 - 20 ng/g, and the recoveries were 87% -101%. The calibration curves showed good linearity in the range of 2 - 1 000 microg/L with correlation coefficients larger than 0.995. The method was also applied to determine common antibiotics and metronidazole in 11 real samples from the market. Chloramphenicol was detected in 2 samples and the concentrations were 0.37% and 0.19%; metronidazole was detected in 1 sample and the concentration was 1.02%; others were not detected.