Poly(۱-Naphthylamine)–Graphene Oxide Nanocomposite Modified Carbon Paste Electrode for the Economical Enzymeless Electrochemical Sensing of Dopamine

Dopamine (DA) is a vital neurotransmitter having key roles in regulating various biological functions in animals and the sensitive and selective monitoring of DA in biological fluid is of high significance. Herein, poly(۱-naphthylamine)–graphene oxide (PNA-۲۰GO) nanocomposite containing ۲۰ % GO by weight obtained by the in-situ chemical oxidative polymerization of ۱-naphthylamine in the presence of GO was utilized to develop an economical electrochemical sensor for DA by modifying Carbon Paste Electrode (CPE) with prepared PNA-۲۰GO nanocomposite. The electrochemical characterization of the PNA and PNA-۲۰GO was performed with Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopic (EIS) studies. The electrochemical response and charge transfer kinetics were significantly improved for the PNA-GO-modified CPE compared to PNA-modified CPE which was evidenced by the comparatively lower diameter of the semicircle region in the Nyquist plot obtained from EIS studies and better current response for the PNA-GO modified CPE than PNA modified or bare CPE in the corresponding CV curves. The enhanced electrochemical characteristics were credited to the increased surface area and synergistic charge transfer interactions between the PNA and GO. Furthermore, it was observed that PNA-GO modification could trigger the diffusion-controlled electrochemical oxidation of DA over CPE. The demonstrated PNA-GO modified DA sensor could show the linear current response for DA concentration ranging from ۱-۱۰۰ µM. The sensor exhibited high sensitivity (۱۰۹۴ µA/(mM.cm۲)) with a low detection limit of ۰.۲۳ µM. The present DA sensor could exhibit acceptable stability and selectivity over common interfering molecules like creatine, ascorbic acid, and uric acid.

کلیدواژه ها:

electrocatalytic ، Conducting polymer ، Differential pulse voltammetry ، Cyclic voltammetry