Kinetic spectrophotometric method for the determination of selenium(IV) by its catalytic effect on the reduction of spadns by sulphide in micellar media

A simple kinetic spectrophotometric method was developed for the determination of ultratrace amounts of Se(IV). The method is based on the reduction of spadns by sulphide in micellar media. The reaction was monitored spectrophotometrically by measuring the decrease in the absorbance of spadns at 515 nm with a fixed-time method. The decrease in the absorbance of spadns is proportional to the concentration of Se(IV) in the range 0.5–100 ng/mL with a fixed time of 2.5–7.0 min from the initiation of the reaction. The limit of detection is 0.3 ng/mL Se(IV). The relative standard deviation for the determination of 0.02 and 0.10 µg/mL Se(IV) was 2.10 and 1.95%, respectively. The method was applied to the determination of Se(IV) in water.