Spectrophotometric flow injection determination of thiocyanate

A new procedure is proposed for the flow injection determination of thiocya nate based on the induction effect of thiocyanate on the oxidation of Nile Blue with bromate in the presence of nitrite in acidic media. The reaction was monitored spectrophotometrically by measuring the decrease in absorbanc e of Nile Blue at 590 nm. The effects of variables on the sensitivity were investigated and the optimum conditions were established. Thiocyanate can b e measured at a rate of 35-45 samples/h in the range 0.010-3.00 mu g with a limit of detection of 0.008 mu g. The relative standard deviation for ten replicate determinations of 0.010 mu g is 1.7%. Thiocyanate in serum and in sewage water samples was determined by the proposed method with satisfacto ry results.