| Laser ablation-inductitively coupled plasma-mass spectrometry (LA-ICP-MS) is a powerful microanalytical technique for the ananlysis of a variety of geological and environmental samples. Because of the great advantages of LA-ICP-MS over other analytical techniques (in situ, real time, highly sensitive, low detection limit and precise, multi-element capability, no chemical dissolution), It has been used to determine trace element abundances and isotope ratios in melt inclusions and minerals in the scale of tens of micrometres.The technology is relatively, and the geochemical information containing of element concentration and isotopic composition is calculated by the correction of mathematical models after analyzing the signal of actual samples and the standard samples’. The matrix matching between standard samples and actual samples will directly affect the accuracy of the analysis results, so the reference materials which’s matrix match actual samples have become the key factor affecting the successful application of this technology.This article discusses the synthetic method of reference materials for in situ microprobe analysis of major and trace elements by using high-temperature furnace. We select GBW07105(GSR-3), GBW07104(GSR-2), GBW07103(GSR-1) and K-feldspar powers which is added lead metasilicate for high temperature fusion, quenching research to obtain basalt glass, andesite glass, granit glass and K-feldspar glass. Major and trace elements’ homogeneity and accuracy is obtained in microprobe analysis by LA-Q-ICPMS, and The Pb isotopic compositions of K-feldspar is analyzed by LA-MC-ICPMS. The following conclusions are obtained:The results show that the optimal synthesis condition is1400℃and4hours. Forty-six kinds of major and trace elements were analyzed by laser ablation-quadrupole inductively coupled plasma mass spectrometer (LA-Q-ICPMS). The results show that the basalt glass’ major and trace elements have good precision and accuracy in microprobe analysis, which are better than10%. In36trace elements, the relative deviations of measured values obtained by LA-Q-ICPMS from the reference values obtained by chemical method are generally better than10%, and the relative deviations of measured values from Sr to U is superior than5%. So the basalt glass can be used as an internal standard material in microprobe analysis.Some elements’standard values (Cr,Rb,Nb,Cs,Tm,Yb,Lu,Pb) in GSR-3are supposed to be amended in this study.Andesite glass’ homogeneity is the best when the experimental condition is1300℃,4hours. So the andesite glass can be used as an internal standard material in microprobe analysis. In35trace elements from7Li to238U, the relative deviations of measured values obtained by chemical method (SN-Q-ICPMS) from the reference values obtained by LA-Q-ICPMS are generally better than10%, but V, Zn and Ga is not very good, may be dued to the contamination of high-temperature melting and fine grinding. In10major elements from23Na to56Fe, the relative deviations of measured values obtained by EMPA method from the reference values obtained by LA-Q-ICPMS are uniform. Primary reference values in GSR-2G are obtained by LA-Q-ICPMS in this study. Some elements’standard values (Nb,Cs,Tb,Tm,Yb,Hf) in GSR-2are supposed to be amended in this study.The results show that the optimal synthesis condition of granit glass is1600℃and4hours. Some elements’relative standard deviations (Cr,Co,Ni,Mo,Zr,Hf) is worse than18%. The relative deviations of measured values obtained by chemical method (SN-Q-ICPMS) from the reference values obtained by LA-Q-ICPMS indicate that Sc,Cr,Co,Ni,Cu is bad,which is dued to local enrichment by high temperature fusion.Because of the volatility in Zn and Pb, the concentration in the granit glass is10%lower than that in the original powder. Other elements’ relative standard (Li,Be,V,Ge,Rb,Sr,Y,Nb,Cs,Ba,REEs,Th and U)is better than10%, which have good accuracy.A K-feldspar glasses synthesizing method using high temperature furnace was reported in this work. The original K-feldspar minerals were crushed and grinded to5μm prior to further melting. The K-feldspar powders was melted in furnace at1680℃for2hours and then quenched in liquid nitrogen to get K-feldspar glasses. The synthesized glasses are used as the standard for Pb isotope ratios in the scale of tens of micrometres.The K-feldspar glasses with different Pb concentration need different fusion times. One fusion time is enough for low Pb concentration glass (20-50ppm),and the Pb isotopic compositions are0.8211±0.0004(207Pb/206Pb,2s).1.8151±0.0017(208Pb/206Pb,2s),19.79±0.25(206Pb/204Pb,2s),16.25±0.20(207Pb/204Pb,2s) and35.96±0.20(208Pb/204Pb,2s), while the relative RSD of these isotopic ratios are0.046%,0.095%,1.28%,1.23%and1.27%. Medium Pb concentration glass (200 ppm) fused three times is better, and the Pb isotopic compositions are0.7624±0.0003(207Pb/206Pb,2s),1.8957±0.0008(208Pb/206Pb,2s),20.885±0.015(206Pb/204Pb,2s),15.922±0.014(207Pb/204Pb,2s)and39.604±0.035(208Pb/204Pb,2s), while the relative RSD of these isotopic ratios are0.032%,0.039%,0.07%,0.09%and0.09%.Homogeneity is good while the high Pb concentration glass (500ppm) only fused one time. The Pb isotopic compositions are0.75895±0.00002(207Pb/200Pb,2s),1.8978±0.0001(208Pb/206Pb,2s),20.919±0.003(206Pb/204Pb,2s),15.875±0.002(207Pb/204Pb,2s) and39.714±0.008(208Pb/204Pb,2s), while the relative RSD of these isotopic ratios are0.002%,0.006%,0.017%,0.014%and0.019%.The results show synthesized K-feldspar contained the medium and high Pb concentration are homogenized, and it can be used as reference materials for in situ microprobe analysis of Pb isotope ratios in K-feldspar. |
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