Determination of low levels of total mercury in blood and plasma by cold vapour atomic fluorescence spectrometry

Abstract

A sensitive and semi - automated analytical method allowing determination of low and normal levels of total mercury in human blood and plasma using cold vapour atomic fluorescence is described. Samples are digested overnight, or at an elevated temperature for 4 h, followed by bromination at room temperature. After reduction with tin (II), analysis is performed using automated continuous flow vapour generation coupled to a fluorescence detector, allowing 20 samples to be analysed per hour. Detection limits for blood and plasma were found to be 0.9 and 0.5 nmol Hg l¹, respectively. The method precision at various concentrations of mercury was determined. For whole blood at 8.1 nmol Hg l¹ and 12.9 nmol Hg l¹, the within - day precision was 5% and 6% and the between-day precision 9% and 6%, respectively. For plasma at 1.3 nmol Hg l¹, the within-day precision was 13% while the between-day precision was 17%. Accuracy was evaluated by an inter - laboratory comparison study. At blood mercury con­centrations below 60 nmol Hg l¹ the results from the current method were almost identical to those obtained with radiochemical neutron activation analysis, commonly regarded as a reference method. The present method should have merits in relation to previously used methods using atomic absorption spectrometry.