In situ Voltammetry Determination of Ascorbic and Oxalic Acids in Juices and Fruits Using an Electrode Modified by a Gold–Palladium Bimetallic System

Abstract

Abstract: We developed a method for the selective and sensitive voltammetric determination of ascorbic and oxalic acids. A screen-printed electrode, modified by gold–palladium bimetallic system and exhibiting catalytic activity in the electrooxidation of the organic acids under consideration, was used as a detector. The difference between the potentials of oxidation peaks of these compounds was 400–500 mV. The proposed method enables an in situ voltammetric determination of ascorbic and oxalic acids in citrus fruits and orange juices without sample preparation. The results of the voltammetric determination are comparable with the data of iodometry and permanganometry, which are the recommended methods for the analysis of fruit juices.