Chitosan Modified Screen-Printed Carbon Electrode for Sensitive Analysis of Heavy Metals

The chitosan-modified screen-printed carbon electrode was used as a working electrode for the determination of selected metals: Pb, Cu, Cd and Hg. In 0.1 M HCl/KCl medium. The chlorocomplexes of these elements form ion-associates with the protonated amino group in the chitosan molecule at the electrode surface, then the resulting accumulated metals were stripped off using differential pulse anodic stripping voltammetry. The experimental conditions were optimized with respect to homemade printing ink composition, chitosan content, preconcentration time and scan rate. With 30 s preconcentration time, limit of detection values were 3.4, 5, 5 and 2 ng mL-1, for Pb, Cu, Cd and Hg, respectively. The relative standard deviation for measuring Pb2+ was 4.1 % (n = 5) using the same electrode and 7 % (n=15) with different electrodes in the same batch. The screen-printed electrodes exhibit adequate shelflife (6 months). There was no interference from Cd, Tl, Zn, Cu, Bi, Sb, Fe, Co, Au, Al, As, Pt, and Mn in Pb2+ determination while Sn showed significant interference. The developed screen-printed carbon electrodes modified with chitosan were successfully employed for the determination of Pb2+ in spiked tape water sample, holding a great promise for decentralized testing of heavy metals.