Disposable plastic electrode for electrochemical determination of total chromium and hexavalent chromium

We report a sensitive electrochemical protocol based on an easy-to-produce and disposable plastic electrode for the determination of total chromium (Cr) and Cr(VI). The electrode was fabricated by sputtering a thin layer of gold on a polyethylene terephthalate (PET) substrate. The experimental factors influencing the fabrication and electrochemical analysis as well as potential interferences were investigated. Under optimum conditions, the determination of total Cr was achieved by adsorptive cathodic stripping voltammetry and the linear range was from 5 to 70 mu g.L-1 and from 70 to 300 mu g L-1 with a limit of detection of 5 mu g L-1. The analysis of Cr(VI) was performed by amperometry and linearity in the range from 0.5 to 100 mu g L-1 with a limit of detection of 0.5 pg L-1 was obtained. The applicability to spiked river water and textile samples was demonstrated with satisfying results. The proposed method has been proved to provide more convenient sensor fabrication and much higher sensitivity than other reports based on disposable electrodes. We believe it may provide a promising alternative for routine analysis of total Cr and Cr(VI).