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 determining 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 a potential step. The electrodeposited Au-NP strongly adsorbs and electrocatalytically reduces Cr(VI), which results in an enhanced reduction current. Compared with the bulk gold electrode, the reduction current of Cr(VI) was 10 times larger with the Au-NP-modified SPE electrode. Square wave voltammetric 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 0.1 ppb Cr(VI) was obtained under optimum experimental conditions. The attractive behavior of the Au-NP-modified SPE holds great promising for onsite environmental monitoring and biomonitoring of Cr(VI)