Extractive spectrophotometric determination of Co(II) at trace level using l-phenyl 1,2-propanedione dioxime

Abstract

Cobalt(II) forms a yellow coloured complex with I-phenyl 1,2- propanedione dioxime (H₂PPDD) which can be extracted into chloroform under optimum conditions. The chloroform extract shows l_max at 345 nm. Beer's law is obeyed over the range of 0.5-4.0 ug ml^-1  of cobalt (II), the molar absorptivity and Sandell sensitivity for cobalt(II) - H₂PPDD system being 6.42 x 10³ mol^-1cm^-1  and 9.17 ng cm^-2 respectively at 345 nm. The composition of the extracted species is found to have 1:2 (metal:ligand) stoichiometry interference due to diverse cations and anions has been investigated. The method has been employed for the determination of cobalt in synthetic and real samples like high speed steel, Vitamin B₁₂ injection and cobalt ink dryer.