Development of a Highly Sensitive Extractive Spectrophotometric Method for the Determination of Nickel(II) from Environmental Matrices Using 2-Acetylpyridine-4-methyl-3-thiosemicarbazone

Abstract

Nickel(II) reacts with 2-acetylpyridine-4-methyl-3-thiosemicarbazone (APMT) and forms a yellow colored complex, which was extracted into n-hexanol from sodium acetate and acetic acid buffer at pH 6.0. The absorbance value of the Ni(II)-APMT complex was measured at different intervals of time at 375 nm to ascertain the time stability of the com-plex. The extraction of the complex into the solvent was instantaneous and stable for more than 72 hrs. The system ob-eyed Beer's law in the concentration range of 0.235 -2.43 µg⋅ml –1 of nickel(II), with an excellent linearity and a cor-relation coefficient of 0.999. The molar absorptivity and Sandell's sensitivity of the extracted species were found to be 2.16 × 10 4 L mol –1 ⋅cm –1 and 0.003 µg⋅cm –2 at 375 nm, respectively. Hence a detailed study of the extraction of nickel(II) with APMT has been undertaken with a view to developing a rapid and sensitive extractive spectrophotometric method for the determination of nickel(II) when present alone or in the presence of diverse ions which are usually associated with nickel(II) in environmental matrices like soil and industrial effluents. Various standard alloy samples (CM 247 LC, IN 718, BCS 233, 266, 253 and 251) have been tested for the determination of nickel for the purpose of validation of the present method. The results of the proposed method are comparable with those from atomic absorption spectrometry and were found to be in good agreement.