Determination of trace amount of thiocyanate in waters and wastewaters sample by a kinetic spectrophotometric method

A simple, sensitive, and selective kinetic spectrophotometric method with no need for removing interfering substances is proposed for determination of thiocyanate ion in water and wastewater samples. The method is based upon the inhibiting effect of the ion on the reaction between sodium bromate and methyl red in acidic medium. The decolorization of methyl red was used to monitor the reaction spectrophotometrically at 518 nm. Thiocyanate can be determined in the range of 0.01- 0.20 μg ml-1 with 3σ detection limit of 1 ng ml-1. The relative standard deviations for 6 replicated determinations of 0.05, 0.12, and 0.18 μg ml-1 thiocyanate were 4.2, 2.6, and 1.5%, respectively. The method was successfully used to determine the thiocyanate content of spiked water and wastewater samples.

Keywords:

Thiocyanate , Methyl red , Kinetic , Spectrophotometric , Determination