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Explore the latest methods for total mercury analysis, mercury and arsenic speciation. Learn about drawbacks of conventional total mercury analysis and discover improved techniques. Gain insights into dimethylmercury, methylmercury, and various mercury forms.
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What we'll discuss • Recent advances in methods for total mercury • Mercury speciation • Arsenic speciation
Conventional total Hg analysis(cold vapor AAS) digest with aqua regia digest with aqua regia oxidize with potassium permanganate oxidize with potassium permanganate add sodium chloride/hydroxylamine sulfate add sodium chloride/hydroxylamine sulfate reduce Hg with stannous sulfate reduce Hg with stannous sulfate 2+ measure evolved Hg by AAS at 253.7 nm measure evolved Hg by AAS at 253.7 nm
Drawbacks of CV-AAS total Hg method • digestion requires 40 minutes/sample mitigated by parallel processing • contamination risk from reagents and processing • interferences from sulfide, chloride, organics • disposal of laboratory waste ….there is a better way
dimethylmercury, methylmercury dimethylmercury, methylmercury neurotoxic, bioaccumulate neurotoxic, bioaccumulate Hg soluble salts Hg soluble salts 2+ toxic, bioavailable, methylated/reduced toxic, bioavailable, methylated/reduced Hg Hg 0 volatile, toxic volatile, toxic HgS HgS stable in anaerobic sediments stable in anaerobic sediments
Toluene KCl/K SO 4 2 Organic Hg Water-Soluble Hg + HgCl HgCH , Hg(CH ) 2 3 3 2 0.2M HNO 3 Dil.-Acid Soluble Hg HgO 1:3 HNO + H O 2 3 HNO -Soluble Hg 3 Hg0 1:6:17 HNO 3 + HCl+ H O 2 HNO /HCl-Soluble Hg 3 HgS Sample