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Ultrasensitive explosive sensors are significant in anti-terrorism and related environment issues. Herein, we proposed a novel boron-doped graphene (B-GE) modified glassy carbon electrode (GCE) applied as a simple, sensitive electrochemical high melting explosive (HMX) sensor. The morphology and structure features of B-GE were characterized. The electrochemical behaviors of HMX on the B-GE modified GCE were investigated by cyclic voltammetry (CV). Under the optimized conditions, CV was used for the quantitative detection of HMX, and the reduction peak current exhibited good linear dependence with the concentration of HMX in the ranges of 2 ∼ 20 μM and 20 ∼ 100 μM. The low detection limit (LOD) was calculated as 0.83 μM (245.81 ppb). Furthermore, the B-GE/GCE showed satisfactory repeatability, high selectivity and stability. The reduction reaction mechanism of HMX on B-GE modified electrode was explored by computational theoretical analysis. Additionally, the differences of the reduction mechanisms from nitroaromatic explosives were discussed. [ABSTRACT FROM AUTHOR]

Highlights: [•] A PEDOT/GO modified electrode was obtained via potentiostatic method using GO as a dopant. [•] The electrochemical behavior of acetaminophen (AP) showed highly reversibility. [•] An electrochemical sensor based on PEDOT/GO was developed for the detection of AP. [•] The sensor shows high sensitivity and selectivity to AP. [ABSTRACT FROM AUTHOR]

Polycarbazole (PCZ)/nitrogen-doped graphene (N-GE) composite was prepared by electropolymerization of carbazole on the N-GE modified glass carbon electrode (N-GE/GCE) for fabricating a novel electrochemical sensor for 4-nitrophenol (4-NP). The PCZ/N-GE shows high conductivity and well-distributed nanostructure. The redox behavior of 4-NP at a PCZ/N-GE/GCE was investigated in acetate buffer solution by cyclic voltammetry (CV), compared with the bare GCE, reduced graphene oxide (RGO), N-GE and PCZ modified GCEs. The results indicate that all modified electrodes show the enhanced reduction peak currents. However, the PCZ/N-GE/GCE exhibits the highest peak current and most positive reduction potential of 4-NP, which reflects the PCZ/N-GE composite has the best electrocatalytic activity towards 4-NP. The enhanced electrochemical performance of PCZ/N-GE and the electrocatalytic activity to 4-NP are contributed to the synergic effect of PCZ and N-GE with highly conductivity and large surface area, which can greatly facilitate the electron-transfer processes between the electrolyte and electrode. An electrochemical sensor for 4-NP was developed based on the PCZ/N-GE modified electrode under the optimized conditions. The reduction peak current was linear with the concentration of 4-NP in the range of 8 × 10 -7 ∼2 × 10 -5 M. The low detection limit of the sensor was estimated to be 0.062 μM (S/N = 3). The sensor based on PCZ/N-GE/GCE was also applied to the detection of 4-NP in real water samples. [ABSTRACT FROM AUTHOR]

A newly fabricated nitrogen-doped graphene (NGE) supported hemin composite was prepared with facile one-pot method deriving from graphene oxide. Hemin was directly anchored on the surface of NGE during the N-doping process with doping-reducing agent of 2-aminopyridine. XPS results revealed the nitrogen doping of graphene and the integration of Hemin with NGE, and the hemin-N C (H-NGE) composite was characterized with TEM and SEM. The peroxidase-like activity of hemin maintained, displaying fast redox property. The H-NGE also exhibited remarkable electrocatalysis towards O 2 and H 2 O 2 reduction due to the high-speed charge-transfer between hemin and the modified electrode. The good electroactivity of NGE and the excellent synergic effect enables an enhanced electrochemical performance. Based on the well-designed H-NGE, the electrocatalytic H 2 O 2 determinations was monitored amperometrically with a low detection limit (0.092 μM). [ABSTRACT FROM AUTHOR]