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Well-dispersed composites of graphene and molybdenum disulfide were synthesized without using a mediator. The composites were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The electrochemical properties of a glassy carbon electrode (GCE) modified with the graphene/MoS composite were investigated by electrochemical impedance spectroscopy and cyclic voltammetry. Hydroquinone was selected as a model target to show the sensing capability of the modified GCE. The GCE, best operated at a working voltage of 0.10 V (vs. Ag/AgCl), exhibits excellent catalytic activity towards hydroquinone, with a linear response in the 0.5 to 300 μM concentration range and a 37 nM detection limit (at an S/N ratio of 3). The superior performance of the GCE is attributed to the synergistic effects of graphene and MoS. [ABSTRACT FROM AUTHOR]

Bisphenol A, an important compound that is classified as an environmental hormone, has been proven to have harmful effects on human health and ecology. A molybdenum disulfide/Au nanorod-modified glassy carbon electrode was prepared as an electrochemical sensor for the detection of bisphenol A using a simple and convenient approach. UV-Vis spectrophotometry and transmission electron microscopy were employed to characterize the composite. The electrochemical behavior of bisphenol A at the modified electrode was investigated via differential pulse voltammetry and cyclic voltammetry. The results show that bisphenol A exhibits a good electrochemical signal at the modified electrode under optimized conditions, and a good linear relationship was observed between the bisphenol A concentration and peak current within the range of 0.01-50 μM, with a detection limit of 3.4 nM. Furthermore, the fabricated electrodes showed good anti-interference, reproducibility and stability. The proposed electrochemical method was successfully applied for the detection of bisphenol A in milk and water samples, and its potential for applications in pollutant detection was demonstrated. [ABSTRACT FROM AUTHOR]

Graphene/Au nanowire (G/Au NW) composites were prepared facilely by mixing well-dispersed graphene and Au nanowires and used to modify the glassy carbon electrodes as a tulobuterol electrochemical sensor. The modification activity of the composites was investigated with the electrochemical impedance spectroscopy technique. A sensitive, rapid and simple electrochemical method was developed for the detection of tulobuterol based on the strong enhancement effect of G/Au NWs. The peak currents varied linearly with the concentration of tulobuterol over the range from 7.6 × 10 −8 to 7.6 × 10 −6 mol L −1 , and the detection limit was 1.36 × 10 −8 mol L −1 ( S / N = 3). The electrode developed can be used for the electroanalytical detection of tulobuterol and provide a potential application of tulobuterol in further research. [ABSTRACT FROM AUTHOR]

Boron nitride (BN) was used as a support and covered with an ionic liquid (IL) and tungsten disulfide (WS2) nanoparticles to obtain an electrode for the determination of 4-aminophenol (4-AP). BN was prepared using a "solvent cutting" method, and the BN-IL-WS2 nanocomposite was obtained by an ultrasonic method. BN and its hybrids were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. When the BN-IL-WS2 composites were coated on the surface of the electrode, the response to 4-AP was strongly amplified due to the strong synergetic effect between the three materials. The voltammetric response of the modified sensor (with a maximum at 0.29 V vs. Ag/AgCl) in solutions with a pH of 6 is linear in the 0.01–50 μΜ 4-AP concentration range, and the limit of detection is 3 nM. A modified glassy carbon electrode was applied for the determination of 4-AP in seawater and dispersions containing paracetamol tablets. The results were consistent with those obtained by HPLC. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2) was used as an electrically conductive skeleton and functionalized with an ionic liquid and gold/silver nanorods. The resulting composite was characterized by scanning electron microscopy, transmission electron microscopy and UV-vis spectroscopy. The composites were used to modify a glassy carbon electrode (GCE) to obtain a sensor for 2,4-dichlorophenol (2,4-DCP). The results show that the oxidation power and electrocatalytic activity of the modified GCE towards 2,4-DCP are enhanced compared to a bare GCE and other modified GCEs. Response is linear in the 0.01 to 50 μM 2,4-DCP concentration range, with a 2.6 nM detection limit. The sensor is highly sensitive and long-term stable. It was successfully applied to the determination of 2,4-DCP in spiked water samples and gave satisfactory recoveries.Schematic of an electrochemical sensor for the differential pulse voltammetric (DPV) determination of 2,4-dichlorophenol. It is based on the use of an MoS2-ionic liquid-Au/Ag nanorod composite. [ABSTRACT FROM AUTHOR]

A dopamine electrochemical sensor was easily fabricated by modifying the glassy carbon electrode with well-dispersed graphene and molybdenum disulfide hybrids. Graphene had the ability to enhance the electrochemical response intensity and molybdenum disulfide served as an amplification element when added to the graphene layer. The modification activity was investigated with the electrochemical impedance spectroscopy technique. A highly sensitive electrochemical method was developed to detect dopamine based on the strong enhancement effect of graphene-molybdenum disulfide. The oxidation peak currents varied linearly with the addition of dopamine over the range from 5.0 × 10 − 8 to 1.0 × 10 − 5 mol L − 1 , and the lower detection limit was 7.13 × 10 − 9 mol L − 1 (S/N = 3). This work demonstrated a simple, efficient design for a chemical sensor that employs graphene-molybdenum disulfide for dopamine detection. [ABSTRACT FROM AUTHOR]