Determination of Thiocyanate at the Nanogram Level by a Kinetic Method

A procedure is reported for the kinetic determination of thiocyanate based on the catalytic effect of thiocyanate on oxidation of sodium azide by iodine at pH 5. The reaction is monitored spectrophotometrically at 348 nm (absorption maximum of iodine). Calibration curves for thiocyanate were linear in the range 1.0 - 2000 ng.ml−1 with the detection limit of 0.3 ng.ml−1 of thiocyanate. The method was applied for the determination of thiocyanate in the water, serum and urine.