Determination of mercury in soils and biological matrices by the vanadium pentoxide digestion procedure.

Abstract

The wet digestion procedure using catalytic amounts of vanadium pentoxide with sulfuric-nitric acid mixture developed in this laboratory for the analysis of mercury in cereals is extended to other biological substrates and soils. Investigations of the different parameters, such as temperature and concentration of vanadium pentoxide on the oxidation process indicate that 0.20 g of vanadium pentoxide was adequate to degrade 5.0 g of animal feed at 70–75°C. Studies have shown that excellent recoveries of mercury are obtained in spite of the presence of excess sulfur-containing amino acids and of certain metallic ions commonly present in soils. This digestion procedure is compared with that using potassium permanganate-sulfuric acid as oxidant to illustrate the significant advantages of this technique. It is found that less quantities of reagents and shorter duration of digestion are required for vanadium pentoxide oxidation than are necessary for potassium permanganate system. The probable role of vanadium pentoxide in the oxidation process is also discussed.