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Optimization of a Wet Digestion Method for the Determination of Mercury in Coal Samples by Cold Vapor Atomic Absorption Spectrometry (CVAAS)

1985; Wiley; Volume: 94; Issue: 5 Linguagem: Inglês

10.1002/bscb.19850940507

0037-9646

R. Dumarey, P. Verbiest, R. Dama,

Laser-induced spectroscopy and plasma

Abstract A comparative study is reported on different wet‐digestion mixtures and reaction vessels for the reduction‐aeration/amalgamation/CVAAS determination of mercury in coal samples. A 100% recovery is obtained when performing the digestion in HNO 3 /HCIO 4 /(NH 4 ) 2 S 2 O 8 at 250–300°C using the Bethge apparatus. Total reaction time is about 30 min. No interference is found by undissolved silicates which are eliminated by filtration. The digests are stable for 24 h. The detection limit is 0.2 ng Hg ml −1 for a 5ml‐fraction analysis, corresponding to 0.08 ppm in the coal. The reproducibility of the entire method is better than 2% above 0.5 ng ml −1 . Results are given for the analysis of standard reference coal samples showing a good agreement with the certified value