The Selective Electrochemical Sensing of Naringin Using Electropolymerized Ellagic Acid Film

Electrochemical sensor on the basis of glassy carbon electrode (GCE) covered with multi-walled carbon nanotubes and electropolymerized ellagic acid (polyEA/MWNT/GCE) has been developed for the naringin determination. Polymeric film has been obtained by potentiodynamic electrolysis. The working conditions of polymeric coverage formation (scans number, supporting electrolyte pH, monomer concentration and electrolysis parameters) providing the best naringin response have been found. Ellagic acid (EA) electropolymerization has to be performed from 10 mu M monomer by sevenfold cycling of potential in the range of 0.0-1.0 V at the scan rate of 100 mV s(-1) in phosphate buffer (PB) pH 7.0. Scanning electron microscopy (SEM) confirms successful modification of the sensor surface with evenly distributed 30-50 nm spherical particles providing 9.6-fold increase of the electrode effective surface area vs GCE. Naringin electrooxidation parameters on polyEA/MWNT/GCE have been found. Sensor acting under conditions of differential pulse voltammetry in PB pH 6.5 provides linear dynamic ranges of 0.050-1.0 and 1.0-100 mu M with the detection and quantification limits of 14 and 47 nM, respectively. The selectivity of sensor towards naringin in the presence of inorganic ions, saccharides, hesperidin, ascorbic and phenolic acids is proved. The sensor developed has been successfully tested on grapefruit juices. (C) 2020 The Electrochemical Society (ECS). Published on behalf of ECS by IOP Publishing Limited.