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Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) is suited to analyze the abundances and spatial distributions of trace elements in sulfide. However, the spread use of the technology on micro area analysis has been hampered by the different characteristics of sulfides from silicates and oxides and the lack of sulfide reference material, especially PGE-bearing reference material. In this study, a PGE-bearing sulfide (SRMD-1) is synthesized by remelted nickel sulfide fire assay button in AN evacuated quartz tube. The examination by BSE imaging revealed that the nickel button SRMD-1 was completely of monosulfide composition. Homogeneity testing by LA-ICP-MS shows that the RSDs of elements, such as S, Ni, Cr, Co, Cu, Pb, Sb, Cd, Bi, are less than 10%. The data suggest the homogeneous distribution of these elements inside SRMD-1, but elements Mn, Zn, Sn, Tl are not as homogeneous with relatively larger RSDs. Elements Ag, Au and Pt are homogeneous inside SRMD-1, but RSDs of other noble metal elements are relatively larger according to low element content, instrument fluctuations or mass spectrometry interference. The homogeneity of the nickel button will be improved by increasing the content for the noble metal elements and lowering the quenching temperature for the molten samples. During the analysis of the nickel sulfide fire assay button, the spectral interferences in light PGEs (Ru, Rh and Pd) by argides is serious, and must be corrected, while the interferences to Os, Ir, Pt and Au can be ignored. Compared to the button which is not remelted, the homogeneity of the elements improved significantly. According to the work documented here, it is possible to synthesized PGE-bearing sulfide reference material for LA-ICP-MS by remelted nickel sulfide fire assay button.

Mg/Ca, Sr/Ca ratios and trace element contents in stalagmites provide important indices for high resolution paleoclimate reconstruction. In situ LA-ICP-MS analysis is introduced here instead of solution methods due to their large errors and mixing with multi-micro layers. The spatial distributions of Mg/Ca and Sr/Ca parallel to the growth axis of stalagmite are compared in sampling ways of line scan and spot ablation respectively, which consistently show significant cyclical variations. The line scan ablation with 40 μm beam spot has the advantages of high stability, high resolution, and of being fast and simple. The relationship of relative sensitivity coefficients and element fractionation are discussed among NIST 610, NIST 612, KL2G, ATHO-G and MASC-3. Indications are that the matrix effect is the main reason for the relative sensitivity coefficient change. The calibration method of 45 major, minor and trace elements in stalagmites was established by using normalization with multi-external standards and internal standard element of Ca. The matrix normalization of Ca and Mg major elements in forms of CaCO3 and MgCO3 with other elements, not only changes the calculation method of the content of the internal standard elements in domestic and foreign studies, when using other analytical techniques, but also avoids the problem of inaccurate detection of carbon successfully, which is consistent with the result when using internal standard element Ca.

Melt inclusions in phenocrysts play a very important role in petrological research for reserving the only direct information available on the temperature, pressure and chemical compositions of the magmatic system at the time that the host minerals crystallized. However, due to the limitation of techniques on sampling method, the resolution and sensitivity of the instrument, the study of melt inclusions (especially the chemical composition) is a relatively slow process. The melt inclusions properties and classifications generally are introduced in this paper, along with a summary of the analytical methods, applications and sample preparation, and an extensive description of the technique of Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS), especially the elemental fraction, matrix effects and principal points for laser ablation. The development of an in-situ micro-analytical technique by LA-ICP-MS, which can analyse the multi-phase inclusions up to 100 μm beneath the surface of the complex minerals, and avoids the prerequisite conditions of heating homogenization and sample preparation for the routine method is described. With the advantages of rapidity, efficiency and accuracy, the newly developed technique allows more analysis for melt inclusions in the same sample and comprehensively provides evolvement information for magma. Data accuracy can be comparable with Electron Microprobe Analysis and Secondary Ion Mass Spectrometry. Recently, this technique has been applied widely in research fields of geology and ore deposit geology. Furthermore, the significant achievements were obtained in the deep earth magmatic processes and magmatic hydrothermal metallogenic theory. The development of the equipment and quantitative methods will improve the accuracy of this technique. Meanwhile, the development and application of in-situ isotopic analysis of melt inclusions by LA-MC-ICP-MS will revolutionize melt inclusions research.

Arnebinones B, E, and D ( 1 - 3 ) have been found to be sensitive to light, generating complex and diverse proton transfer products when triggered by light. A unique two-step irreversible intramolecular proton transfer of 1 produced five scalemic mixtures, of which four possessed intriguing dual planar chirality. The unprecedented orientation epimerization equilibrium of the intra-annular double bond was first observed and researched in the homologous meroterpenoids by HPLC monitoring and DFT calculations. A " p -benzoquinone-CH 2 /CH-π" moiety in the structure was the common key feature for the occurrence of this type of photoenolization reaction. The product transformation processes and universality of this photoinduced irreversible proton transfer reaction were analyzed together with the cytotoxic activities of arnebinones B, D, and E, and their photoreaction products.

Matrix effect between reference materials and samples is one of the major factors affecting the accuracy of analytical results by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). However, there is no method or calculation formula to quantify matrix effect between standards and samples up to date. In this paper, the linear correlation coefficient r of the Ii/I(is-Ci)/Cis graphs of element pairs were used to characterize the matrix effect, which took the ratios of concentrations (ci/ c(is)) and intensities (Ii/Iis) of the analytical element and internal standard element as x-axis and gamma-axis, respectively. Matrix effects of 6 element pairs in 13 glass reference materials, 2 sulfide reference materials and 2 sulfide minerals using Fe as internal standard was studied, with the linear correlation coefficient r of Fe-Cu, Fe-Zn element pairs both less than 0. 999 and trace Fe--Mn, Fe--Co, Fe--Ga, Fe--Pb element pairs all better than 0.999. Matrix effects of 3 major element pairs in 2 sulfide ref- erence materials and 6 sulfide minerals using S as internal standard was also studied, with the linear correlation coefficient r of S--Fe, S--Cu, S--Zn all less than 0.999. The great majority of relative errors of EMPA analytical results for major elements in sulfide minerals were greater than 10%, whether analyzed using Fe as internal standard with glass reference materials as external standard, or S as internal standard with sulfide reference materials MASS-1, IMER-1 as external standard, respectively. But the most analytical results for trace elements calibrated by glass reference materials using Fe as internal standard were well agreed with sulfide standard MASS-1, with the relative errors less than 15%. The results showed that matrix effects existed in glass reference materials, sulfide reference materials and sulfide minerals, and it also proved a certain rationality and practicability for quantification of matrix effect using the linear correlation coefficient r of the Ii/Iis-Ci/Cis graphs by this element pair method. This study also indicated that trace elements in sulfide minerals could be calibrated using Fe as internal standard with non-matrix matched glass reference materials as external standard, especially for NIST610 contained nearly all the trace elements in sulfide minerals and with relative high concentrations of each element, which obtained analytical results agreed well with sulfide standard MASS-1.