Abstract

NAGLES, Edgar, ARANCIBIA, Verónica, RIOS, Roxana et al. Determination of traces of cadmium in the presence of morin-5´-sulphonic acid as complexing agent by adsorptive stripping voltammetry (AdSV) on hanging mercury drop electrode (HMDE). Rev. Soc. Quím. Perú, Apr./Jun. 2012, vol.78, no.2, p.71-78. ISSN 1810-634X.

A simple and sensitive electroanalytical method is developed for the determination of cadmium by adsorptive stripping voltammetry (AdSV) in the presence of morin-5'-sulphonic acid (MSA). The Cd (MSA)₂ complex accumulates on the surface of a hanging mercury drop electrode (HMDE) and peak current is measured by square wave voltammetry (SWV). The complex is reduced at -0.69V. The experimental variables as pH, MSA concentration (C_MSA), accumulation time (t_acc), accumulation potential (E_acc), as well as potential interferences, are investigated. Under the optimized conditions (pH 3.9; C_QSA 2.5 µmol L^-1; t_acc 80s; E_acc -0.30 V), peak current is proportional to the concentration of Cd(II) over the 0.1 to 12.0 µg L^-1 range, with a detection limit of 0.1 µg L^-1. The relative standard deviation for a solution containing 10.0 µg L^-1 of Cd(II) solution was 1.08% for seven successive assays. The method was validated by determining Cd(II) in synthetic sea water (ASTM D665) spiked with ICP multielement standard solution and in certified reference water (SPS-WW1). Finally, the method was successfully applied to the determination of Cd (II) in tap water after UV digestion.

Keywords: Cadmium; adsorptive stripping voltammetry; morin-5´-sulphonic acid.