Determination of chromium,iron and selenium in foodstuffs of animal origin y collision cell technology,inductively coupled plasma mass spectrometry ICP-MS),after closed vessel microwave digestion

摘要

The determination of chromium(~(52)Cr),iron(~(56)Fe)and selenium(~(80)Se)isotopes in foodstuffs of animal origin has been performed by collision cell technology(CCT)mode using an inductively coupled plasma mass spectrometry(ICP-MS)as detector after closed vessel microwave digestion.To significantly decrease the argon-based interferences at mass to charge ratios(m/z): 52(~(40)Ar~(12)C),56(~(40)Ar~(16)O)and 80(~(40)Ar~(40)Ar),the gas-flow rates of a helium and hydrogen mixture used in the hexapole collision cell were optimised to 1.5ml min~(-1)H2 and 0.5rnl min~(-1)He and the quadrupole bias was adjusted daily between -2 and -15 mV.Limits of quantification(LOQ)of 0.025,0.086 and 0.041 mgkg~(-1)for Cr,Fe and Se,respectively,in 6% HNO_3 were estimated under optimized CCT conditions.These LOQ were improved by a factor of approximately 10 for each element compared to standard mode.Precision under repeatability,intermediate precision reproducibility and trueness have been tested on nine different certified reference materials in foodstuffs of animal origin and on an external proficiency testing scheme.The results obtained for chromium,iron and selenium were in all cases in good agreement with the certified values and trueness was improved,compared to those obtained in standard mode.