Digestion of 0.5 g air dried sample with 10 mL HNO3 acid in a microwave digestion vessel for 10 minutes. The sample is further digested for 2 h with 0.25 M H2SO4, 5% potassium permanganate & 5% potassium persulfate in a hot water bath at 95oC. After reduction with stannous chloride, the Hg is quantified by the cold vapor technique using atomic absorption spectrophotometry on a mercuryMonitor Elemental Mercury Detector.
(See Method References No. 36 & 37)