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COMPREHENSIVE ANALYSIS OF BIOLOGICALLY RELEVANT ARSENICALS BY PH-SELECTIVE HYDRIDE GENERATION-ATOMIC ABSORPTION SPECTROMETRY
Citation:
Drobna, Z., S. B. Waters, V. Devesa, M Styblo, L. M. Del Razo, M F. Hughes, AND D J. Thomas. COMPREHENSIVE ANALYSIS OF BIOLOGICALLY RELEVANT ARSENICALS BY PH-SELECTIVE HYDRIDE GENERATION-ATOMIC ABSORPTION SPECTROMETRY. Presented at Society of Toxicology, Baltimore, MD, March 21-25, 2004.
Description:
A method based on pH-selective generation and separation of arsines is commonly used for analysis of inorganic, methylated, and dimethylated trivalent and pentavalent arsenicals by hydride generation-atomic absorption spectrometry (HG-AAS). We have optimized this method to permit quantification of trimethylated arsenicals. Increasing adsorbent density in the cold trap (to increase the number of theoretical plates) and optimizing the temperature gradient during release of arsines from the cold trap, improved the separatory power of this method. This optimized technique permits analysis of most common biologically relevant arsenic species, including arsenite (iAsIII), arsenate (iAsV), monomethylarsonic acid (MAsV), monomethylarsonous acid (MAsIII), dimethylarsinic acid (DMAsV), dimethylarsinous acid (DMAsIII), and trimethylarsine oxide (TMAO). Selective generation of arsines of trivalent species and TMAO at pH 6, and of all arsenicals (trivalents and pentavalents) at pH 1 permits quantification of each species. Calibration curves are linear for analyte concentrations of 0.5 to 100 ng and recoveries range from 85 and 124%. The variation of the method does not exceed 15%. The method is equally effective for analyses in aqueous solutions and in simple biological matrices (urine or cell lysates). The optimized technique has been used to analyze arsenical metabolites in cultured human hepatocytes exposed to iAsIII and in urine of mice treated with MAsV or DMAsV. Methyl- and dimethylated arsenicals, but not TMAO, were detected in hepatocytes or culture medium. Considerable amounts of TMAO were found in urine of mice treated with MAsV or DMAsV. Hence, this optimized HG-AAS technique can be used for comprehensive analysis of arsenicals in biological matrices that do not require extraction before assay. (This abstract does not reflect US EPA policy).