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R9 Laboratory SOP 517
ANALYSIS OF SOLID SAMPLES FOR MERCURY
Summary
This SOP describes the standard and sample preparation steps of solid samples and the instrumental analytical procedures for mercury by cold vapor atomic absorption (CVAA) The samples are analyzed using the Leeman PS200 Automated Mercury Analyzer. This method is applicable for the preparation of soils, solids, sludges and tissues for total mercury (organic + inorganic) by EPA Method 7471B.
The Region 9 Laboratory quantitation limit (QL) is 0.04 mg/Kg for total mercury analyzed using the Leeman PS200.
An aliquot of a solid sample is transferred to a BOD bottle or equivalent closed-system container. The sample is digested with aqua regia, and a dilute potassium permanganate-potassium persulfate solution for 30 minutes at 95°C. The digestion oxidizes all forms of mercury to Hg(II). The Hg(II) in the digested sample is reduced with stannous sulfate to elemental mercury which is sparged from the sample and detected by atomic absorption.