Spectrophotometric Microdetermination of Divalent Cu, Ni, Pd and UO2 Ions Using Some Naphthoic Acid Azo Dyes

Abstract

Spectrophotometric studies have been carried out on five hydroxynaphthoic acid azo dyes and their metal complexes in aqueous solution at pH 5–8. These azo dyes have been proved as good analytical reagents for the microdetermination of Cu (II), Ni (II), Pd (II) and UO₂ (II) ions based on measuring their absorbance at 470–535 nm and by the photometric titration using EDTA as a titrant. Interference of various cations and anions in this method was studied to find out the most suitable azo dyes for the microdetermination of the respective metal ions. Beer's law was obeyed for Cu (II) and Ni (II) up to 5.8 ppm, for Pd (II) up to 8.5 ppm and for UO₂ (II) ions up to 16.6 ppm.