Kinetic-spectrophotometric determination of trace amounts of selenium(IV) based on its catalytic effect on the reduction of brilliant green by sulphide ion

A simple, rapid and sensitive kinetic-spectrophotometric method for the determination of trace amounts of Se(IV) (0.02-2.50 mug ml(-1)) based on its catalytic effect on the reduction of brilliant green by sodium sulphide is reported. The reaction is followed spectrophotometrically by measuring the rate of decrease in absorbance of the brilliant green at 625 nm and 25 degreesC. A fixed time method of 1.5 min from initiation of the reaction has been used. The limit of detection is 12 ng ml(-1) and the relative standard deviation for ten replicate analysis of 1 mug ml-1 of Se(IV) is 1.25%. The parameters influencing the sensitivity have been optimized. The proposed method has been used for the determination of Se(IV) in an antiseborrheic 1% selenium sulphide shampoo.