Chitosan-ZnO/polyanilne nanocomposite modified glassy carbon electrode for selective detection of dopamine

In this study, inorganic-organic redox mediators of CS-ZnO/PANI nanocomposite were synthesized by simple precipitation and chemical polymerization approach in the presence of chitosan (CS), ZnCl2, polyaniline (PANI) and ammonium peroxydisulfate (APS) as an initiator. The formation of ZnO nanoparticles onto CS-PANI matrix was confirmed by SEM, TEM, Raman and FT-IR spectroscopies. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used to evaluate the electrochemical performance of the CS-ZnO/PANI. The obtained CS0.12-ZC2.5/PANI nanocomposite modified electrode has been successfully developed for selective determination of dopamine (DA) in the presence of ascorbic acid (AsA) in 0.2 M phosphate buffer solution pH 7.0. The electrochemical oxidation signals of AsA and DA are well separated into two distinct peak potential separation of 303 mV in DPV studies, which is large enough to allow the determination of one in the presence of the other. A linear response for DA concentrations range from 20 × 10−5 to 180 × 10−5, in the presence of 140 × 10−5 AsA, with sensitivity of 0.013 μA μM−1 and a detection limit of 0.21 μM, have been obtained. Moreover, CS0.12-ZC2.5/PANI modified glassy carbon electrode (GCE) had good stability and antifouling properties. The proposed biosensor offers promise for simple and cost-effective analysis of bio-molecules.