MICROWAVE DIGESTION TECHNIQUE FOR THE DETERMINATION OF TOTAL CADMIUM IN SOILS

A rapid method is described for the determination of total cadmium (Cd) in soils. The soil samples and standard sediment samples were digested in a microwave oven using concentrated HNO3 and also by the conventional HF-HClO4 digestion in platinum crucibles. The Cd content in the extracts was determined using graphite furnace atomic absorption spectro-photometry (GFAAS). Both digestion methods produced comparable quantitative values for total Cd of standard reference materials obtained from the National Institute of Standards and Technology and a series of surface and subsurface soil samples. Thus, the microwave digestion technique was shown to be an accurate and rapid method for digesting soil samples prior to total Cd analysis.