Synthesis of a New Hydroxytriazene Derivative and its Application for Selective Extraction- Spectrophotometric Determination of Nickel(II)

Abstract

A new hydroxytriazene derivative (3-hydroxy-3-phenyl-l-o-trifluorophenyl triazene, triazene-I) was synthesized and investigated as a selective complexing ligand for the extractionspectrophotometric determination of Ni²⁺ ions. The yellowish Ni(II)-triazene-I complex was extracted from an aqueous solution (pH = 8.5) into a chloroform layer and its absorbance was measured at 410 nm (lmax). The absorbance obeyed Beer's law over the range of 2.0 x 10^-6 to 8.0 x 10^-5 M, with a molar absorptivity of about 1.8 x 10⁴ L mol^-1 cm^-1. The limit of detection was found to be 5.0 x 10^-7 M of Ni²⁺ ion. The influence of pH, shaking time, volume ratio, concentration of the complexing ligand, ionic strength, temperature and the effect of diverse ions on the extraction and determination of Ni²⁺ ions were investigated. Job's method was applied for indicating the stoichiometry of the complex. Also, K_f and ΔG of the complex were estimated. The proposed method was successfully applied to the extraction and determination of Ni²⁺ ion in soil samples.