Research On Determination Of Selenium Isotope Abundance In Clausthalite

The essential trace element, selenium, is of fundamental importance to human health.Selenium plays an important role in biochemistry, environment, geochemistry and so on fields.Selenium isotopes can be tracer agents in geochemistry reactions.Thus,it is of great importantance to develop a precision method for the determination of selenium. The researches on determination of selenium isotopes abundance are fewer, and the researches by corrected determination mass spectrometry are almost vacancy.A method has been developed for determination of selenium isotopes abundance in clausthalite by corrected determination mass spectrometry using multiple collector inductively couple plasma mass spectrometry (MC-ICP-MS).The clausthalite was separation and enrichment, while concentrated isotopes were purification and quantitative dissolved to prepare corrected solutions.According to measurement of the corrected coefficient, selenium isotopes abundance in clausthalite can be confirmed.In the present dissertation, enrichment and separation of selenium in clausthalite with microwave digestion and thiol cotton fiber (TCF) was carried out.After microwave digested, selenium was reduced to unified valence and improved the experimental device to control the flow rate in separation.The results showed that when the flow rate was 0.04 ml·s-1,the maximum recovery of selenium can be achieved by 98%,and the separation efficiency of main impurity elements was up to 97%.The selenium isotope abundance was determined by multiple collector inductively couple plasma mass spectrometry(MC-ICP-MS),the detection of Se isotope abundance ratio in sample which used the pretreatment method has good agreement with unused one. It showed that the pretreatment method for determination of selenium isotopes abundance is feasible.The Se concentrated isotopes had been purified with the way of vacuum evaporation, the purity of Se concentrated isotopes after purified were all up to 0.9999 and was up to the mustard for preparing corrected solutions.The concentrated isotopes were blended to prepare synthetical isotope samples by gravimetry using exact balance. According to measurement of selenium isotope abundance by MC-ICP-MS,the corrected coefficient was calculated, then selenium isotopes abundance in clausthalite can be confirmed.