Kinetic–spectrophotometric determination of diquat based on a charge-transfer complex with cysteine
Abstract
The reaction involving the formation of a charge-transfer complex between diquat and cysteine was studied. The initial rate of the reaction, measured as a change in absorbance at 495 nm during 60 s, was linearly related to diquat concentrations from 0.5 to 28.0 µg cm–3. The applicability of the method was demonstrated by the determination of diquat in commercial herbicides, waters, soils and potatoes.