Abstract
A spectrophotometric method for the determination of dithianone, 2, 3-dicyano-1, 4-dithiaanthraquinone, was studied and established. The recommended method is as follows. A sample containing 150mg of dithianone was weighed into a 100ml measuring flask and it was filled up with acetone. After one hour of standing with occasional shakings, one ml of the supernatant was pipetted into a 50ml measuring flask and made up to 50ml with methanol. Five ml of the solution was pipetted into a 25ml measuring flask. The flask was filled up with 3% aqueous sodium sulfide solution held at 25°C and immediately the absorbancy of the solution at 375mμ was measureed. The amount of dithianone was calculated from the calibration curve obtained by treating 5ml of the standard solution containing 100200μg of dithianone through the procedure mentioned above.
It was clarified by thin-layer chromatography that commercial products of dithianone did not contain any substance which interfered with the analysis. The method was proved to be applied to the determination of dithianone in its formulations containing other fungicides, i.e. phenylmercuric acetate, Cellocidin or basic cupric chloride.
