A selective complexometric method is described for the determination of mercury(II) using sodium metabisulphite as a masking reagent. An excess of EDTA is added to mercury(II) solution containing associated diverse metal ions and the surplus EDTA is back titrated at pH 5-6 (hexamine buffer) with standard zinc sulphate solution using xylenol orange as indicator. An aqueous solution of sodium metabisulphite is then added to displace EDTA selectively from Hg-EDTA complex and the released EDTA is then titrated against the same standard zinc sulphate solution. Reproducible and accurate results are obtained in the range 4-100 mg of mercury with a relative error ? 0.26% and coefficient of variation ?0.40%. The method is useful for the analysis of mercury in complexes and alloy samples.
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Complexometric method for the determination of mercury using sodium metabisulphite as selective masking reagent
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Abstract
2004
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Keywords
alloy, buffer, edetic acid, mercury, metal ion, methenamine, reagent, sodium metabisulfite, unclassified drug, xylene, xylenol orange, zinc sulfate, accuracy, acidity, aqueous solution, article, error, reproducibility, titrimetry
Citation
Indian Journal of Chemical Technology, 2004, 11, 2, pp. 163-165