Isotope Dilution Analysis of Selenium in Biological Materials by Nitrogen Microwave-Induced Plasma Mass Spectrometry

Abstract

Nitrogen microwave-induced plasma mass spectrometry was applied to isotope dilution analysis of selenium in biological matrices. The precision of isotope ratio ( 80 Se/ 78 Se) measurements of a 100 ng/mL standard solution was 0.5% under practical analysis conditions and could be after lowered by increasing the integration time. spectroscopic interference at m/z=80 arising from SO 3 + was observed, but the extent was not so much as to cause a serious problem at the sulfur level normally found in biological materials. Isotopic ratios in digested clinical specimens pod well with those in the standard solution, indicating no other spectroscopic interferences on selenium isotopes in real samples. The proposed method was successfully applied to the analysis of selenium in biological reference materials. The results showed good agreement with the certified values