Electrochemical Sensors Base On The Modification Of Graphene Composite

Graphene has attracted more and more attention due to its excellent conductivity and mechanical properties ever since it was first reported. Moreover, it has been applied widely in basic researches and industrial field. Graphene oxide which posseses many advantages like having quantity of oxygen-containing groups,has good biocompatibility and solubility, high specific surface area. It can be used to prepare nanofilm by the combination of polymers or nanoparticles. We can see its bright future in the domain of electrochemical sensors. The technology of electrochemical biosensors is easier to manipulate and could be monitored constantly. Therefore, it appears to be important scientific significance and application prospects to explore the electrochemical methods of detecting amine, phenols ect. In this paper, polymers and nano metal oxide are used to modify graphene oxide to prepare the electrochemical biosensors of amine, phenols. Besides, electrochemical mechanism of these sensors is also discussed so as to provide a new approach to testing these substance. The work of this thesis is summarized as follows:(1)A electrochemical sensor based on GO/nano ZnO composite film was developed by self-assembly for simultaneous determination of catechol(CC), hydroquinone(HQ) and resorcinol(RC). The GO/ZnO modified electrod presented high sensitivity and selectivity towards CC, HQ and RC, and showed three pairs of independent and obvious redox peaks. The parameters such as accumulation potention and time which influlence the currents of CC, HQ and RC were investigated by linear sweep voltammetry(LSV). Under optimized conditions, linear calibration graphs were obtained in the range of 0.2μM~126μM, with a detection of limit of 0.031μM, for CC, in the range of 1.1μM~206μM, with a detection of limit of 0.35μM, for HQ, and in the range of 1.58μM~81μM, with a detection of limit of 0.15μM, for RC.(2) A nanocomposite material(rGO-PEG) was synthesized by polyethyleneglycol(PEG) functionalized graphene through a simple and gentle way. The composite was used to modify glassy carbon electrode and construct a electrochemistry sensor. The sensor was applied to detect 4-acetamino phenol, hydroquinone and catechol, the limit of detection were 9.74 nM, 2.62 nM and 1.56 nM respectively(S/N = 3). Used to detect AP levels in the cold tablet, the recovery is satisfactory.(3) A rapid and sensitive electrochemical sensor based on GO-PVA Nano-composite film modified glassy carbon electrode for the detection of ractopamine was developed. The influences of the pH value of buffer solution and sweep rate on the catalysis of ractopamine were studied by cyclic voltammetric. It was proved that ractopamine had good electrochemical behaviors on GO-PVA/GCE modified electrode. The detection of ractopamine was carried out by amperometry and the detection limit was as low as 0.032μM. What’s more, the electrochemical sensor was successfully used in the detection of ractopamine in pork. The result showed that the recoveries were between 92.6% and 100.4% and the relative standard deviation(RSD) was less than 8%.