Determination of Total and Inorganic Mercury in Hair by Flameless Atomic Absorption, and of Methylmercury by Gas Chromatography

Abstract

Abstract A new procedure for alkaline digestion of hair was used for the selective determination of total and inorganic mercury by flameless atomic absorption and the determination of methylmercury by an improved gas-chromatographic procedure. The precision of the measurements by atomic absorption for total, inorganic, and organic mercury (by difference) was 1.9%, 6.5%, and 2.1%, respectively. Recoveries ranged from 98 to 99.4%. The precision of the measurements of methylmercury by gas chromatography was 3.7% and the recovery 95.6%. Individual samples were corrected for recovery by using radiolabeled methylmercury. A high level of correlation (r = .99) was found between methylmercury as measured by gas chromatography and organic mercury as determined by atomic absorption. Contamination of hair by external applications of mercurials was differentiated from mercury deposited in hair from the diet by means of a special washing procedure, which removed selectively the externally absorbed Hg0, Hg2+, and CH3Hg+. The internally deposited mercury was shown to be stable in spite of exposure to various cosmetic and washing treatments.