Simple and rapid determination of mercury in urine and tissues by isotope exchange

The method eliminates oxidation of organic material. Tracer quantities of (203)Hg are added to the sample and equilibrated with the stable mercury. (200)Hg vapor in nitrogen is passed through the sample in the presence of cysteine and at pH 7.4, and exchanges with the (203)Hg. The vapor is collected in a tube of activated Hopcalite placed in a gamma-counter. The increasing activity is recorded and the half-time of exchange is directly proportional to the mercury concentration in the sample. The method is best suited for urine samples containing more than 10 mug Hg l .