Inorganic, Organic, and Total Mercury in Blood and Urine: Cold Vapor Analysis with Automated Flow Injection Sample Delivery

A cold vapor atomic absorption technique for blood or urine mercury analysis that uses persulfate oxidation to prepare samples for total mercury analysis and acid permanganate oxidation to prepare samples for inorganic mercury analysis is described. The linearity of the procedures ranged from 0.5 to 25 µg/L. Precision ranged from 20% at 1 µg/L to 7% at 20 µg/L. Documentation of accuracy is based on analysis of samples prepared by an international proficiency survey program. The development of a two-step digestion procedure followed by automated flow-injection mercury analysis was a necessary precursor to the assessment of inorganic and alkylmercury exposure in a large unexposed human population. Application of this technique to 902 blood and 902 urine samples collected from a normal human population who had no extraordinary mercury exposure generated mean plus two standard deviation skewed confidence-limit ranges of results as follows: blood total mercury, 0–8.4 µg/L; blood inorganic mercury, 0–1.7 µg/L; blood organic mercury, 0–7.5 µg/L; urine total mercury, 0–9.9 µg/L; urine inorganic mercury, 0–8.6 µg/L; and urine organic mercury, 0–1.8 µg/L.