1-PHENYL-1,2-BUTANEDIONE DIOXIME AS A NEW REAGENT FOR THE EXTRACTIVE SPECTROPHOTOMETRIC DETERMINATION OF CO(II) AT TRACE-LEVEL

Cobalt(II) forms yellow coloured complex with 1-phenyl 1, 2-butanedion e dioxime (H2PBDD) which can be extracted into chloroform under optimu m conditions. The chloroform extract shows absorption maximum at 355 n m. The Beer's law is obeyed over the range of 0.5 - 5.0 mu g mL(-1) of cobalt(II), the molar absorptivity and Sandell sensitivity for cobalt (II) - H2PBDD system being 6.30 x 10(3) L mol(-1) cm(-1) and 9.34 ng c m(-2) respectively at 355 nm. The composition of the extracted species has been determined by Job's variation and by mole ratio method and i s found to have 1 : 2 (metal : ligand) stoichiometry. Interference due to diverse cations and anions has been investigated. The method devel oped has been employed for the determination of cobalt in synthetic an d real samples like alloys, pharmaceutical and an ink dryer.