Novel Electrodes Based on the Electropolymerized Nanocoatings for the Selective Voltammetric Quantification of Flavanones

Abstract

: Chemically modified electrodes based on polymer nanocoatings as sensitive layers are one of the intensively developed areas in modern electroanalysis. Electropolymerization of compounds containing phenolic fragments is a promising approach for electrode surface modification. Novel electrodes based on a combination of carbon nanotubes and electropolymerized ellagic acid or aluminon were developed for the direct quantification of flavanones (naringin and hesperidin)— the major flavonoids of Citrus fruits. Conditions of monomers’ potentiodynamic electropolymerization were optimized. Electrodes surface was characterized by scanning electron microscopy and electrochemical methods. A glassy carbon electrode (GCE) modified with multi-walled carbon nanotubes (MWCNTs) and poly(ellagic acid) allowed quantification of naringin in the ranges of 0.050–1.0 and 1.0–100 µM with the detection and quantification limits of 14 and 47 nM, respectively. Simultaneous voltammetric quantification of naringin and hesperidin in the ranges of 0.10–2.5 and 2.5–25 µM for both analytes with the detection limits of 20 nM and 29 nM for naringin and hesperidin, respectively, was achieved on GCE modified with polyaminobenzene sulfonic acid functionalized single-walled carbon nanotubes (f-SWCNTs) and polyaluminon. High selectivity of the elec-trodes’ response to flavanones in the presence of typical interferences and natural phenolics was confirmed. The approaches were successfully applied to citrus juices.