2-chlorobenzaldehyde thiocarbohydrazone: a novel reagent for liquid-liquid extractive spectrophotometric determination of copper(II) from environmental and real samples

Abstract

ABSTRACT 2-Chlorobenzaldehyde thiocarbohydrazone (2-CBTCH) is proved as a novel analytical chelating reagent to developa simple, fast and selective liquid–liquid extractive spectrophotometric method for trace level determination of copper(II). The method was based upon the complexation reaction of copper(II) with 2-CBTCH in ethanol. It instantly forms orange coloured [Cu(II)-2 CBTCH] complex at room temperature, which was quantitatively extracted in 1-butanol and shows maximum absorption at 470 nm. The values of molar absorptivity and Sandell’s sensitivity of [Cu(II)-2CBTCH] complex are found to be 0.3429 × 104 Lmol−1 cm−1 and 0.01851 µgcm−2, respectively. The system follows Beer’s law up to 17.5 µgmL−1. The stoichiometry of the [Cu(II)-2CBTCH] complex in 1-butanol is determined by Job’s method, mole ratio method is 1:2 and was confirmed by log-log plot method. To intuit the peak extraction conditions several experimental factors such as pH, reagent concentration, selection of solvent, shaking time, interference of cations and anions has been studiedwell. The usage of masking agent lifts the selectivity of the present method. The method has been effectively used for the determination of copper(II) in alloy samples, pharmaceutical samples, fertiliser samples and environmental samples such as leafy vegetables and water samples.