The electrocatalytic oxidative polymerization of o-phenylenediamine by reduced graphene oxide and properties of poly(o-phenylenediamine)

Electrodeposited reduced graphene oxide-PEDOT:PSS/Nafion hybrid interface for the simultaneous determination of dopamine and serotonin

The electrochemically deposited reduced graphene oxide-PEDOT:PSS/Nafion (rGO-PP/NF) hybrid material has provided a favorable interface for the simultaneous detection of dopamine (DA) and serotonin (5-HT). The rGO-PP/NF onto the Au seed layer of the flexible substrate was simple, and it was followed by the sequential electrophoretic deposition of GO, reduction at the optimal pH buffer media, electropolymerization of EDOT:PSS, and Nafion coating. The strong electron-transport capacity between rGO-PEDOT:PSS and the negatively charged Nafion matrix might allow the highly sensitive, simultaneous, and selective detection of DA and 5-HT due to its high affinity for cations. In the results of the electrochemical response, well-separated oxidation peaks were observed in a mixture that contained various concentrations of DA and 5-HT. It showed the dynamic sensing of DA and 5-HT in the ranges of 0.5-75 μM and 0.05-50 μM, respectively, and the detection limits of 0.17 and 0.16 μM, respectively. In the mixture of DA and 5-HT, the sensor had a detection limit of 0.1 μM for 5-HT and DA, and its sensitivities of DA and 5-HT were 99.3 and 86 µA/µMcm2. Furthermore, it demonstrated high selectivity, reproducibility, stability, and a recovery property in the human serum spike test that was good enough for the practical use.

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

D-penicillamine (PA) is a sulfur group-containing drug prescribed for various health issues, but overdoses have adverse effects. Therefore, regular, selective, and sensitive sensing is essential to reduce the need for further treatment. In this study, diphenylamine (DPA) was electropolymerized in an aqueous acidic medium. The PA detection sensitivity, selectivity, and limit of detection were enhanced by electropolymerizing DPA on an electrochemically reduced graphene oxide (ERGO)/glassy carbon (GC) surface. The formation of p-DPA and ERGO was investigated using various techniques. The as-prepared p-DPA@ERGO/GC revealed the excellent redox-active (N-C to N=C) sites of p-DPA. The p-DPA@ERGO/GC electrode exhibited excellent electrochemical sensing ability towards PA determination because of the presence of the -NH-functional moiety and effective interactions with the -SH group of PA. The p-DPA@ERGO/GC exhibited a high surface coverage of 9.23 × 10-12 mol cm-2. The polymer-modified p-DPA@ERGO/GC electrode revealed the amperometric determination of PA concentration from the 1.4 to 541 μM wide range and the detection limit of 0.10 μM. The real-time feasibility of the developed p-DPA@ERGO/GC electrode was tested with a realistic PA finding in human blood serum samples and yielded a good recovery of 97.5-101.0%, confirming the potential suitability in bio-clinical applications.

M. P. Heterocyclic aminopyrazine–reduced graphene oxide coated carbon cloth electrode as an active bio-electrocatalyst for extracellular electron transfer in microbial fuel cells

In the present study, a low molecular heterocyclic aminopyrazine (Apy)–reduced graphene oxide (r-GO) hybrid coated carbon cloth (r-GO–Apy–CC) was employed as an active and stable bio-electro catalyst in a microbial fuel cell (MFC).

Electrocatalytic synthesis of poly(2,6-diaminopyridine) on reduced graphene oxide and its application in glucose sensing

Due to the electrocatalytic reduction of H₂O₂ at the PDAP-RGO, a sensitive platform for glucose sensing was constructed.

Synchronous electrosynthesis of poly(xanthurenic acid)-reduced graphene oxide nanocomposite for highly sensitive impedimetric detection of DNA

A novel and simple synchronous electrochemical synthesis of poly(xanthurenic acid, Xa), electrochemically reduced graphene oxide nanocomposite (PXa-ERGNO), via cyclic voltammetry (CV) was reported, where graphene oxide (GNO) and Xa monomer were adopted as precursors. The resulting PXa-ERGNO nanocomposite was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, CV and electrochemical impedance spectroscopy (EIS). The π-π interactions between the conjugated GNO layers and aromatic ring of Xa-enhanced the electropolymerization efficiency accompanied with an increased electrochemical response of PXa. The rich carboxyl groups of PXa-ERGNO film were applied to stably immobilize the probe DNA with amino groups at 5' end via covalent bonding. The captured probe could sensitively and selectively recognize its target DNA via EIS. The dynamic detection range was from 1.0 × 10(-14) mol/L to 1.0 × 10(-8) mol/L with a detection limit of 4.2 × 10(-15) mol/L due to the synergistic effect of integrated PXa-ERGNO nanocomposite. This graphene-based electrochemical platform showed intrinsic advantage, such as simplicity, good stability, and high sensitivity, which could serve as an ideal platform for the biosensing field.