A Study on the Methyl and Ethylmercury Artifacts in Biological Samples Using Sodium Tetra(n-Propyl)Borate as a Derivatizing Agent

Abstract

Sodium tetra (n-propyl) borate was used as derivatizing agent to measure methyl and ethylmercury compounds. This study investigated the artifact formation of methyl and ethylmercury compounds during derivatization using NaBPr4, simultaneously with the influence of this artifact on methylmercury analysis in biological samples (chlor alkali hair samples). The artifact methylmercury and ethylmercury compounds during derivatization using NaBPr4 were evident and depended strongly on the amount of inorganic mercury (Hg2+) present in the sample solution for derivatization and depended on the purity of sodium tetra (n-propyl) borate reagent. The high formation rate of artifact Et-Hg (0.76–0.81% of high-level Hg2+ present) interferes strongly with the ethylmercury analysis. The rate of artifact formation of Me-Hg is small and constant at the different concentration ranges of In-Hg (0.012% of In-Hg present) and does not affect on Me-Hg analysis and it can be subtracted from this Me-Hg artifact ratio from the measured value of Me-Hg in the biological samples. However, the mathematical correction for Me-Hg measurement can be done only when the Et-Hg peak is already appearing in the chromatogram samples.