SPECTROPHOTOMETRIC DETERMINATION OF MANEB BY TERNARY COMPLEX-FORMATION WITH PAR AND CTAB

A rapid, simple, direct, and sensitive method has been developed for the determination of maneb (manganese ethylenebisdithiocarbamate) based on the formation of manganese-4-(2'-pyridylazo) resorcinol complex by a ligand displacement reaction, which is rendered water soluble by a cationic surfactant cetyltrimethylammonium bromide (CTAB) by the formation of an ion association complex. Beer's law is obeyed over the concentration range 0.08-2.4 mu g/ml of the final solution at 500 nm in pH range 8-12. The molar absorptivity and Sandell's sensitivity are calculated to be 8.84 x 10(4) l.mol(-1).cm(-1) and 0.003 mu g/cm(2), respectively. The developed method has been applied to the determination of maneb in commercial formulations, synthetic mixture, grain samples and vegetables.