Development Of Non-Enzymatic Electrochemical P-Nitrophenol Sensor Based On Carboxylated Graphene Oxide Modified Glassy Carbon Electrode

The current work reports a new electrochemical p-nitrophenol (p-NP) sensor which depends upon the carboxyl functionalized graphene oxide (GO-COOH) modified of glassy carbon electrode (GCE). Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were performed to examine the morphology of GO-COOH. The GO-COOH/GCE sensor was electrochemically characterized by means of chronoamperometry, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and linear sweep voltammetry (LSV). A distinct cathodic peak of p-NP was seen on the GO-COOH/GCE in 0.1 M phosphate buffer solution (pH 6.5). The sensor displayed three dynamic linear ranges for p-NP under optimum conductions. The linear detection ranges were 2.0×10-7 - 2.95×10-6 M, 2.95×10-6 – 2.74×10-4 M, and 2.74×10-4 – 7.25×10-4 M with the sensitivities of 39622.1 A/Mm2, 9959.3 A/Mm2, and 6395 A/Mm2, respectively. It was found that detection limit (LOD) was 5.3×10-8 M at a signal to noise ratio of 3. The GO-COOH/GCE demonstrated satisfactory performance factors such as selectivity and repeatability. Additionally, the GO-COOH/GCE sensor was demonstrated to be utilized to electrochemically determine p-NP in a variety of water samples.