The determination of silver in whole blood and its application to biological monitoring of occupationally exposed groups

Abstract

A sensitive and rapid technique for directly measuring silver in blood, using electrothermal atomization atomic absorption spectrophotometry (ETAAS) is described. The method can be used to analyse precisely up to 40 blood samples a day in duplicate. Well-mixed, whole blood samples, collected in EDTA, were diluted 1 + 4 with a diluent containing 40 g l.-1 ammonium dihydrogen orthophosphate and 0.5 ml l.-1 Triton X-100. Aliquots of diluted blood were then analysed by ETAAS using wall atomization with a pyrolytically coated tube. The coefficient of variation for within-run precision was 4.55% at 10 micrograms 1.-1 and 5% at 25 micrograms 1.-1 Between-run variation, it was 4.1% at 25 micrograms l.-1 The analytical recovery for the method was 98% +/- 3% at both 8 and 30 micrograms 1. -1 The detection limit of the method was 0.1 microgram 1. -1, which was sufficiently sensitive to distinguish exposed from non-exposed individuals. Blood silver levels in unexposed subjects were found to be between < 0.1 and 0.2 micrograms 1. -1. Blood silver levels were determined in 98 occupationally exposed workers involved in bullion production, cutlery manufacture, chemical manufacture, jewelery production and silver reclamation. Blood silver levels ranged from 0.1 to 23 micrograms 1.-1, with some of the highest levels found in silver reclaimers.