Abstract

This article describes the quantitative determination of Cu(II) using thermal lens spectrometry. The chromogenic reaction involving Cu(II) and 5-(4-sulphophenylazo)-8-aminoquinoline in alkaline solution was studied in different experimental conditions such as pH, ligand concentration, methanol volume, and presence of interfering ions. A collinear dual beam set-up has been used for direct quantitation in water samples without a pre-concentration step. The optimized conditions provided a linear calibration in the concentration range from 3.0 to 15.0 x 10(-7) mol L-1. The detection and quantitation limits were 6.13 x 10(-8) and 2.04 x 10(-7) mol L-1, respectively. Resultantly, an application to Cu(II) determination in tap water (recovery 99.8-103.3%) and mining (synthetic) wastewater (95.3-98.0%) shows relative SDs <= 3.1%. The method is presented as a new alternative for the direct Cu(II) determination in real samples.