Voltammetric detection of Cr(VI) with disposable screen-printed electrode modified with gold nanoparticles

Gold nanoparticle (Au-NP) enhanced voltammetric detection of Cr(VI) is developed for determination of trace amounts of Cr(VI) in an acetate buffer media (pH 4.6). The Au-NPs were electrodeposited onto a disposable screen printed electrode (SPE) via an electrodeposition step. It was found that the electrodeposited Au-NP has strong adsorption on Cr(VI) species, which results in an enhanced reduction current of Cr(VI). Compared with the bulk gold electrode, the reduction current of Cr(VI) was enhanced 10 times with the Au-NP-modified SPE electrode. Square wave voltammetric (SWV) measurement with the disposable Au-NP-modified SPE provides a fast, simple and sensitive detection of trace amounts of Cr(VI). The adsorption of Cr(VI) on Au-NP was characterized with voltammetry, X-ray photoelectron spectroscopy and ultraviolet spectra. The different parameters including the electrodepositing time, supporting electrolyte, and pH that govern the analytical performance of the electrode have been studied in detail and optimized. The detection limit of 5 microg L(-1) Cr (VI) was obtained under optimum experimental conditions. The performance of the sensor was successfully evaluated with river water samples spiked with Cr(VI), indicating this convenient and sensitive technique offers great promise for onsite environmental monitoring and biomonitoring of Cr(VI).