Kinetic Spectrophotometric Determination of Trace Amounts of Thiocyanate Based on its Catalytic Effect on the BromateCrystal Violet Reaction in Biological Samples

Abstract

A new analytical method was developed for determination of the thiocyanate content of
spiked water and biological samples. This method is based upon the catalytic effect of the ion
on the reaction between sodium bromate and crystal violet (CV) in acidic media. The
decolourisation of CV was used in order to monitor the reaction spectrophotometrically at 630
nm. The variables affecting the reaction rate were determined and optimized. The method is
simple, rapid, relatively sensitive and precise. The limit of detection (3σ) was 6 ng mL-1
and the
calibration range was linear over the thiocyanate concentration range of 10-1250 ng mL-1
. The
relative standard deviations for ten replicate determinations of 0.250, 0.500 and 1.00 Åg mL-1
were 4.36%, 3.04% and 1.11%, respectively. Influences of the potentially interfering substances
were also studied. The method was successfully used to determine the thiocyanate content of
spiked water and biological samples.