Study On Graphene-based Electrochemical Sensing

Graphene is a new nanomaterial, with small particle size, large specific surface area, high surface reactivity, high catalytic efficiency and strong adsorption ability of the excellent properties of new type structure of carbon. Currently, Graphene has shows the potential application value in the field of sensors, super capacitor, superconductor, nano-electronical appliance and nanocomposite material, etc. As the derivatives of graphene, graphene oxide has a larger specific surface area and can undertake a variety of surface functionalized modifications with good water solubility and biocompatibility, which opens up broad prospects in biosensor field. Graphene with good water dispersibility and composites of graphene oxide/trypsin and grapheme/Au NWs were successfully preparated, and were used to detect formoterol tartrate and bovine serum albumin(BSA) as well as tulobuterol, respectively. The experimental results showed that the sensors used for the detection of formoterol tartrate and bovine serum albumin(BSA) as well as tulobuterol were not only simple and quick, but have the characteristics of high accuracy and good selectivity.(1) In alkaline environment, sodium borohydride was used as reducing agent for the reduction of graphene oxide and graphene with good water dispersibility was successfully preparated. The graphene modified glassy carbon electrode was used to investigate the electrochemical behaviors of formoterol tartrate with cyclic voltammetry and differential pulse voltammetry as well as the effects of different experimental conditions. After optimized the experimental conditions, the response current of formoterol tartrate had a good linear relationship over the range from 3.64×10-7 to 1.64×10-4 mol·L–1, and the detection limit was 7.89×10-8 mol·L–1(S/N=3). Electrochemical testing results showed that graphene modified glassy carbon electrode can be used for the detection of formoterol tartrate with a quick response and the characteristics of good reproducibility and stability.(2) Trypsin was immobilized on graphene oxide(GO) through functionalizing 1-pyrenebutyric acid(PBA) and amine-polyethylene glycol-amine(NH2-PEG-NH2). GO-PBA-PEG-trypsin was characterized by Fourier Transform Infrared Spectroscopy, and observed by Transmission Electronic Microscopy, which revealed trypsin was immobilized on the surface of GO sheets. An ultrasensitive biosensor for detecting bovine serum albumin was investigated based on GO-PBA-PEG-Trypsin modified glassy carbon electrode. The results showed that a wide linear range was from 4.0×10-10 to 4.0×10-7 g·m L-1 and the detection limit was 3.6×10-11 g·m L-1(S/N=3). The biosensor exhibited high sensitivity and reproducibility to provide an applicable way for sensor development.(3) Gold nanowires and graphene/Au NWs composite material were successfully preparated in this study. The electro-catalytic property of the grapheme/Au NWs modified electrodes was tested though cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) methods. An electrochemical sensor for detecting tulobuterol was investigated based on graphene/Au NWs modified glassy carbon electrode. The results showed that a wide linear range was 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) for tulobuterol of this sensor. The sensor exhibited high sensitivity and reproducibility in the actual samples tested.