Selective electronalysis of peracetic acid in the presence of a large excess of H2O2 at Au(1 1 1)-like gold electrode

Abstract

Peracetic acid (PAA) has been selectively electroanalyzed in the presence of a large excess of hydrogen peroxide (H2O2), about 500 fold that of PAA, using Au (111)-like gold electrode in acetate buffer solutions of pH 5.4. Au(111)-like gold electrode was prepared by a controlled reductive desorption of a previously assembled thiol, typically cysteine, monolayer onto the polycrystalline gold (poly-Au) electrode. Cysteine molecules were selectively removed from the Au(111) facets of the poly-Au electrode, keeping the other two facets (i.e., Au(110) and Au(100)) under the protection of the adsorbed cysteine. It has been found that Au(111)-like gold electrode positively shifts the reduction peak of PAA, while, fortunately, shifts the reduction peak of H2O2 negatively, achieving a large potential separation (around 750mV) between the two reduction peaks as compared with that (around 450mV) obtained at the poly-Au electrode. This large potential separation between the two reduction peaks enabled the analysis of PAA in the presence of a large excess of H2O2. In addition, the positive shift of the reduction peak of PAA gives the present method a high immunity against the interference of the dissolved oxygen.