Revista de la Sociedad Química del Perú
Print ISSN 1810-634X
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 (CMSA), accumulation time (tacc), accumulation potential (Eacc), as well as potential interferences, are investigated. Under the optimized conditions (pH 3.9; CQSA 2.5 µmol L-1; tacc 80s; Eacc -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.
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