An innovative method to electrochemical branching of chitosan in the presence of copper nanocubics on the surface of glassy carbon and its electrical behaviour study: A new platform for pharmaceutical analysis using electrochemical sensors

Chitosan (CS) as biocompatible and non-toxic polymer is derived from de-acetylation of chitin and consists of N-acetylglucosamine and glucosamine unites. The ability of CS to form solid deposits similar to hydrogels and the possibility of electrodeposition on the surface of the electrode as a thin film, makes it valuable for the preparation of micro-sensors and nano-biosensors. In this work, a novel method for the electrochemical branching of CS on the surface of glassy carbon was introduced. New modified copper electrodes were fabricated as electrochemical sensors for the determination of mefenamic acid and Indomethacin. Two types of modified copper electrodes; the first based on Cu nanocubes (NC) to identify mefenamic acid, and the other one based on chitosan modified by Cu NCs to detection of indomethacin. Electrochemical behavior and morphology of the copper nanocubes modified copper electrode CuNCs/CuE and chitosan modified copper nanocubics coated on copper electrode (CS-Cu NCs/CuE) were studied using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). The results confirmed the presence of CS-Cu NCs/Cu NCs on the electrode surface. Also, using CV technique it has found that Cu NCs and PCS-Cu NCs led to increased oxidation peak current, by adsorption of indomethacin. However, the anodic peak current was increased by CuNCs for the mefenamic acid. There is a linear relationship between the anodic peak current and mefenamic acid/indomethacin concentration in the range of 1 nM to 10 mM, where the low limit of quantification (LLOQ) was 1 nM for the those drugs. Therefore, the prepared electrodes have many benefits such as high sensitivity, selectivity, and stability for the determination of mefenamic acid and indomethacin in human serums and pharmaceutical preparation.