SPECTROPHOTOMETRIC DETERMINATION OF ZIRAM AND ZINEB WITH 1-(2'-PYRIDYLAZO)-2-NAPHTHOL (PAN)

A rapid, simple, sensitive and selective spectrophotometric method has been developed for the determination of ziram (zinc dimethyldithiocarbamate) and zineb (zinc ethylenebisdithiocarbamate). The zinc-PAN complex is extracted into isobutyl methyl ketone in the pH range 9.0-11.0 and absorbance measured at 550 nm against a reagent blank. Beer's law is obeyed over the concentration range 0.2-2.2 mug/ml and 0.5-2.4 mug/ml respectively. The molar absorptivity is found to be 5.06 x 10(4) dm3 mol-1 cm-1. The values of Sandell's sensitivity are 0.0063 mug cm-2 and 0.0055 mug cm-1 for ziram and zineb respectively. The interferences of various other ions and pesticides have been studied. The method has been tested for the determination of ziram and zineb in commercial formulations, synthetic mixtures, grain and in the presence of various other pesticides.