Determination of Hg and Se in biological materials by chemical vapor generation electrothermal vaporization inductively coupled plasma mass spectrometry using isotope dilution calibration after microwave-assisted digestion with Aqua Regia

摘要

A method for the determination of Hg and Se in biological materials by chemical vapor generation electrothermal vaporization inductively coupled plasma mass spectrometry (CVG-ETV-ICP-MS) using isotope dilution calibration after acid digestion is proposed. The samples were digested with aqua regia in a microwave oven. The isotope ratios used for quantification were: 201Hg/202Hg and 77Se/82Se. A NaBH4 solution stabilized with NaOH was used as reducing agent. The retention and vaporization temperatures in the graphite tube were 150 and 2000 oC, respectively. Six certified biological materials were analyzed and the obtained concentrations were in good agreement with the certified values according to the t-test for a confidence level of 95%. The detection limits in the sample were 0.7 and 3 ng g-1, for Hg and Se respectively. The method is precise, accurate and adequate for the analysis of biological samples in routine and demonstrates the feasibility of using isotope dilution for the proposed system.