Electropolymerized Diphenylamine on Functionalized Multiwalled Carbon Nanotube Composite Film and Its Application to Develop a Multifunctional Biosensor

Abstract

Diphenylamine (DPA) monomers have been electropolymerized on the amino‐functionalized multiwalled carbon nanotube (AFCNT) composite film modified glassy carbon electrode (GCE) by cyclic voltammetry (CV). The surface morphology of PDPA‐AFCNT was studied using field‐emission scanning electron microscopy (FE‐SEM). The interfacial electron transfer phenomenon at the modified electrode was studied using electrochemical impedance spectroscopy (EIS). The PDPA‐AFCNT/GCE represented a multifunctional sensor and showed good electrocatalytic behavior towards the oxidation of catechol and the reduction of hydrogen peroxide. Rotating‐disk electrode technique was applied to detect catechol with a sensitivity of 1360 µA mM−1 cm−2 and a detection limit of 0.01 mM. Amperometric determination of hydrogen peroxide at the PDPA‐AFCNT film modified electrode results in a linear range from 10 to 800 µM, a sensitivity of 487.1 µA mM−1 cm−2 and detection limit of 1 µM. These results show that the nano‐composite film modified electrode can be utilized to develop a multifunctional sensor.

Development of Polydiphenylamine@Electrochemically Reduced Graphene Oxide Electrode for the D-Penicillamine Sensor from Human Blood Serum Samples Using Amperometry

“…The CV trace of 10 cycles was performed in the potential window from −0.40 V to +1.30 V in 1 mM DPA monomer with 0.1 M H 2 SO 4 supporting electrolytes. In the first CV cycle, a broad anodic peak (Epa1) appeared at +0.55 V, corresponding to the positively charged nitrogen species of radical cation formation, followed by radical rearrangement [ 36 ]. These monomer radicals transform, dimerize, and join to form the p-DPA polymer ( Figure 3 ).…”

“…In the reverse scan, cathodic peaks at +0.26 V to +0.4 V were observed, which correspond to the reduction of the dimeric and oligomeric products by electron/protonation. In the second cycle, the CV trace exhibited peaks at +0.32 V and +0.42 V ascribed to p-DPA oxidation and DPA monomer further deposition/conversion as a cation radical to oligomer on the ERGO/GC surface [ 36 ]. During the third and subsequent cycles, the anodic peak at +0.32/+0.23, with progressive increases in the peak current, suggests that the dimers undergo electrochemical oxidative polymerization resulting in the continued growth of p-DPA films on the ERGO/GC electrode surface.…”

“…The scan rate effects were examined from 5 to 500 mV s −1 in the 0.1 M H 2 SO 4 supporting electrolyte to understand the electrochemical properties of the p-DPA@ERGO/GC-coated electrode ( Figure 6 A). CV traces of p-DPA@ERGO/GC showed well-defined anodic and cathodic peaks, corresponding to the conversion of p-DPA and N,N -diphenylbenzidine protonation of the N atom in the polymer backbone [ 36 ]. The anodic/cathodic peak currents increased with increasing scan rate.…”

“…The GO/GC coated electrode was subjected to electrochemical reduction in PBS (0.2 M, pH 7.2) by CV cycling over the potential range of 0.0 V to −1.5 V with fifteen sweeps to achieve the ERGO/GC. The ERGO/GC electrode underwent electropolymerization of DPA by cycling between the potential window of −0.4 V to +1.3 V in the presence of 1 mM DPA in 0.1 M H 2 SO 4 supporting electrolyte, which yielded the p-DPA@ERGO/GC [ 36 ]. Similarly, the p-DPA@GC electrode was obtained using the same procedure on the GC surface.…”