Extractive spectrophotometric determination of nickel (II) using 4-methyl 2,3-pentanedione dioxime (H₂MPDDO)

Abstract

A new analytical reagent, 4-methyl 2,3-pentanedione dioxime (H₂MPDDO), is proposed for the extraction and spectrophotometric determination of nickel. H₂MPDDO reacts with nickel (II) to give yellow coloured complex, which can be quantitatively extracted into chloroform at pH 9.0. The organic extract shows maximum absorption at 370 nm where absorption due to a similarly prepared reagent blank is negligible. The Beer’s law is followed in the concentration range 0.5-10 mg/ml of nickel (II). The molar absorptivity and Sandell’s sensitivity of Ni (II)-(H₂MPDDO)₂ complex are 3.039x10³ l/mol/cm and 0.0192 mg/ml/cm², respectively. The stoichiometry of extracted species was found to be 1:2 (M:L). The proposed method is rapid, sensitive, reproducible and accurate, and has been satisfactorily applied for the determination and separation of nickel in synthetic mixtures and spent catalyst samples.