Kinetic-Spectrophotometric Determination of Thiocyanate Based on Its Inhibitory Effect on the Oxidation of Pyrogallol Red by Bromate

A kinetic spectrophotometric method for rapid measurement of thiocyanate in serum, urine and sewage water with no need for removed of interfering substances in described. The method is based on the inhibitory effect of thiocyanate on the oxidation of pyrogallol red by bromated and nitrite which is monitored at 467 nm. The variables affecting the rate of the reaction were investigated and the optimum conditions were established. Thiocyanate can be measured in the range of 0.010-0-0.500 mg/mL with a limit of detection of 0.001 mg/mL. The relative standard deviation for ten replicate determination of 0.025 mg/mL of thiocyanate is 1.5%.