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-butanedione dioxime (H 2 PBDD) which can be extracted into chloroform under optimum conditions. The chloroform extract shows absorption maximum at 355 nm. The Beer's law is obeyed over the range of 0.5-5.0 μg/mL of cobalt(II), the molar absorptivity and Sandell sensitivity for cobalt(II)-H 2 PBDD system being 6.30x10 3 L/mol.cm and 9.34 ng/cm 2 respectively at 355 nm. The composition of the extracted species has been determined by Job's variation and by mole ratio method and is found to have 1:2 (metal:ligand) stoichiometry. Interference due to diverse cations and anions has been investigated. The method developed has been employed for the determination of cobalt in synthetic and real samples like alloys, pharmaceutical and an ink dryer.