Kinetic Spectrophotometric Determination of Phenylhydrazine Based on Its Inhibitory Effect on the Oxidation of Crystal Violet by Bromate in Micellar Medium

Abstract

A new, simple and selective kinetic spectrophotometric method is described for the determination of trace amounts of phenylhydrazine, which is based on its inhibitory effect on the reaction between crystal violet and bromate in acidic and micellar medium. The reaction was monitored spectrophotometrically by measuring the change in absorbance of crystal violet at 630 nm. The calibration graph was linear in the range of 0.20-1.2 μg/mL. The detection limit (3δ) was 0.12 μg/mL. The relative standard deviations for 6 replicate measurements of 0.5 and 0.8 μg/mL of phenylhydrazine were 1.9 and 2.5 %, respectively. The potential interfering substances were studied in the presence of phenylhydrazine. The proposed method was applied to the analysis of water samples.