Spectrophotometric determination of the fungicide dithianon in aqueous formulation Delan-Col with 2,4-dinitrophenylhydrazine
A simple and specific spectrophotometric method for determining dithianon in Delan-Col, based on reaction between the carbonyl groups of the fungicide and 2,4-dinitrophenylhydrazine, is described. It consists in dissolving the sample in an acetone-chloroform mixture, removing the solvents and refluxing the residue in neutral methanolic 2,4-dinitrophenyl-hydrazine. The resulting solution is made alkaline with methanolic N sodium hydroxide to give an amber colour, the optical density of which is measured at 550 nm. The error of the method was 2·1 per cent.