▎ 摘　　要

Trace amount of arsenate in the presence of arsenite was determined directly on pencil graphite electrode modified by graphene oxide and zirconium (Zr-G-PGE). The layer-by-layer modification of PGE was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). Key point of the developed method was quick adsorption of arsenate than arsenite on the Zr-G-PGE. In optimal conditions, the Zr-G-PGE was applied for determination of arsenate using differential pulse voltammetry in a linear range 0.10-40.0gL(-1) with a limit of determination of 0.12 +/- 0.01gL(-1). The sensitivity of the electrode was 1.36 +/- 0.07A/gL(-1). The modified electrode was used to measure the concentration of arsenate in the river water. A recovery test was performed by introducing 10gL(-1) arsenate into the rivers water in order and acceptable data of average recovery of 101.2% was obtained. From the experimental results, the as-prepared electrode can provide a satisfactory method for direct determination of arsenate in real samples.