A simple and sensitive electroanalytical method is developed for the determination of lead by adsorptive stripping voltammetry (AdSV) in the presence of morin-5′-sulfonic acid (MSA) and sodium dodecyl sulfate (SDS). The Pb-MSA 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 -0.48 V and peak current increases when low concentrations of SDS are added to the sample solution. The experimental variables pH, MSA concentration (CMSA); accumulation time (tacc); accumulation potential (Eacc), and SDS concentration (CSDS), as well as potential interferences, are investigated. Under the optimized conditions (pH 3.2; CMSA: 0.5 μmol L-1; tacc: 60 s; Eacc: -0.35 V, and CSDS: 20 μmol L-1), peak current is proportional to the concentration of Pb(II) over the 0.1-32.0 μg L-1 range, with a detection limit of 0.04 μg L-1. The relative standard deviation for a solution containing 5.0 μg L-1 of Pb(II) solution was 1.5% for seven successive assays. The method was validated by determining Pb(II) in synthetic sea water (ASTM D665) spiked with ICP multi-element standard solution and in certified reference water (GBW08607). Finally, the method was successfully applied to the determination of Pb(II) in tap water and sea water after UV digestion.
Bibliographical noteFunding Information:
Financial support by FONDECYT under project 1080524 is gratefully acknowledged.
- Adsorptive stripping voltammetry
- Sodium dodecyl sulfate