Determination of environmental sulphide requires non-interference from other anions. Cyanide stabilisation of the transient red-violet product of the pentacyanonitrosylferrate(II)-sulphide reaction enables effective quantification of a 0.3 to 5 working range and a 0.2 μg ml-1 limit of detection. Sulphide in standard 2.0 μg ml-1 solutions was detected to within 2.4% standard deviation. The technique has been applied to hot-spring water, marshland water and boiled eggs. The mean sulphide levels were 1.7 ± 0.2, 9.9 ± 0.2 and 21.7 ± 0.2, which compared favourably with 1.9 ± 0.3, 10.9 ± 0.3 and 22.6 ± 0.3 μg ml-1, respectively, by iodimetry.
Key words: Environmental sulphide, determination, Pentacyanonitrosylferrate(II)-sulphide reaction, cyanide stabilization.
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