Bismuth as Internal Standard for Reliable Detection of Trace Lead at Screen-Printed Electrode

摘要

In this paper, bismuth served as an internal standard used for reliable anodic stripping voltammetric determination of trace lead at screen-printed carbon electrodes. Besides its negligible concentration in water samples, bismuth can form alloy with lead and their anodic stripping peaks can be separated obviously. The influence of three electrode pretreatment methods and various experimental parameters upon the stripping signal was investigated. Under optimized conditions, the response ratio I_(Pb)/I_(Bi), against the concentration of lead was linear in the 2-200 μg L~(-1) concentration range with a correlation coefficient of 0.998 after 2 min deposition. The practical application of this method was carried out for the determination of lead in river water samples and the results were consistent with the values obtained by ICP-MS. The attractive behaviors of the low cost carbon strip electrodes coupled with the reliable quantitative strategy facilitates the development of portable electrochemical sensing platform.