MERCURY IN SEDIMENT AND TISSUE SAMPLES

2.1 A representative portion of sample is digested in a microwave unit (a variation of Method 3052) using nitric and hydrochloric acids in a closed fluorocarbon container. The sample is digested under pressure to aid in the dissolution of organic compounds containing mercury. 2.2 An aliquot of the digested sample is diluted and subjected to cold digestion with an acid/bromate/bromide mixture. 2.3 Stannous chloride is added to the digested sample as a reducing agent to produce Hg0. The reduced mercury is separated from the sample/reagent mixture as a vapor that is carried to the fluorescence detector by a stream of high purity argon.