Measurement of total mercury in biological specimens by cold vapor atomic fluorescence spectrometry

An ultrasensitive method for determining total mercury concentrations in biological specimens is a prerequisite for monitoring exposure to chronic low-dose levels of Hg vapor such as those from dental silver amalgam fillings. The clinical consequences of such doses are currently in question. We describe an adaptation of a two-stage gold amalgamation preconcentration step combined with cold vapor atomic fluorescence spectrometric detection for Hg. At Hg concentrations of 40 and 350 nmol/L, the within-day assay CVs were 5% and 3%, respectively; between-day assay CVs were 8% and 5%, respectively. Accuracy, as demonstrated by analytical recovery, ranged from 98% to 105%. The detection limit for the assay is 50 pmol/L, which is suitable for measuring total Hg concentrations in specimens of human urine, blood, and breast milk, and in monkey kidney cortex and feces, obtained from subjects with and without amalgam fillings.