Development of an electroanalytical method to control quality in fish samples based on an edge plane pyrolytic graphite electrode. Simultaneous determination of hypoxanthine, xanthine and uric acid

Abstract

A simple, rapid and non-expensive method is proposed to determine hypoxanthine (Hx), xanthine (Xa) and uric acid (UA) in untreated fish samples based on an edge plane pyrolytic graphite electrode (EPPGE). The square wave voltammetry was the electrochemical technique used. In addition, the experimental design and multi-response assays were used to optimize the pretreatment of the working electrode. Therefore, the EPPGE is used in the simultaneous determination of these analytes for the first time. The optimal accumulation conditions of the analytes on the surface of the working electrode were obtained through a composite central design. The linear range was from 0.1 to 50μM for Hx and Xa, and from 0.1 to 25.0μM for UA. The limits of detection (LOD) were 0.08, 0.06 and 0.03μM for Hx, Xa and UA, respectively. Recovery assays were made in order to validate the proposed method. Recovery percentages were between 90 and 110%. Therefore, the method is a good, simple and fast option for the simultaneous determination of Hx, Xa and UA in fish samples, allowing to perform a control quality of samples.