Automatic method for quantitation of mercury in blood, plasma and urine.

Here we report our experience of quantification of mercury in blood, plasma and urine by using modifications of a procedure for cold vapour atomic absorption. We have tried: (1) modifications of the instrumentation including the tower, the cell and apparatus for measurement; (2) to increase the volume of sample, avoiding problems caused by foaming and background to arrive at a reliable method with low detection limit. Blood and plasma samples were digested overnight in a mixture of nitric acid and perchloric acid (1:5). Recovery of known additions of mercury was close to 100%. Coefficients of variation (CV) within runs and between runs was for B-Hg 4.7 and 9.5, respectively at 20 nmol/l, and for U-Hg 1.8 and 5.2, respectively at 57 nmol/l. The same detection limit of 5 nmol/l was obtained with blood, plasma and urine. This is in the lower range of non-occupationally exposed normal subjects. The results, including those obtained in sample exchange with other laboratories and with reference materials, indicate that the accuracy of this method for quantification of mercury is good.