p-Chloroisonitroso Acetophenone Thiosemicarbazone as an Extractive Reagent for the Spectrophotometric Determination of Zn(II)

Abstract

A new method is developed for the extractive spectrophotometric determination of Zn(II) at microgram level by using 4-chloroisonitrosoacetophenone thiosemicarbazone as an analytical reagent. Zinc(II) forms coloured complex with 4-chloroisonitrosoacetophenone thiosemicarbazone which can be extracted into chloroform in the pH range under optimum conditions. Chloroform extract shows maximum absorbance at 397 nm. Beer's law is obeyed over the range 0.8 to 12 μg/mLof Zn. The molar absorptivity calculated is 3.96 × 10³ L mol^–1 cm^–1 at 397 nm and Sandell's sensitivity is observed to be 0.0016 μg cm^–1. The composition of the extracted species is obtained from mole ratio method, Job's continuous variation method and slope into ratio method are found to be 1 : 2 (M : L) stoichiometry. Interference due to various cations and anions has also been invested. The stability of the complex is observed to be up to 48 h. The developed method has been successfully applied for the determination of Zn(II) in alloys, pharmaceuticals and synthetic mixtures. The method is comparable with the known method.