Preparation Of Graphene Composites Materials Chemically Modified Electrode And Its Application

The discovery of graphene, not only won the Nobel Prize in 2010 and caused the scientific community to the nano structure of carbon material of a new round of research boom. With its excellent conductivity, chemical stability, large specific surface area and good biocompatibility etc, graphene and related materials of chemical modified electrodes become calls hot research topic in the field of analytical chemistry in recent years. Especially on the basis of graphene composites, such as graphene and carbon nano material other compounds; Graphene with metal nanoparticles and its oxide composite materials; Graphene and conductive polymer composite materials are caused by the height of the electroanalysis chemistry workers interests. Graphene composite material combines the advantages of the two materials, synergy between them, which has faster electron mobility, larger specific surface area, better biocompatibility. This paper adopts the method such as electrochemical deposition method, in situ chemical reduction method, respectively, the preparation of poly melamine/graphene composites, nanometer gold/graphene composites, multi-walled carbon nanotubes/graphene composites and nano gold/multi-walled carbon nanotube/graphene composites modified electrodes, using a variety of methods of modified electrodes have been characterized. On this basis, the uric acid is studied respectively, dopamine, isoniazid, bisphenol A and nitrite on the modified electrodes in the electrochemical properties, and set up related electrochemical analysis method of the material in sample. This research work in the development of graphene materials in the application of electrochemical sensors, electrochemical methods of analysis to improve related material properties, enriching the content of the study of the chemical modified electrodes and so on all has the vital significance. This thesis mainly content is as follows:1.A poly-(MA)/ERGO hybrid film modified electrode had been fabricated by using cyclic voltammommetry. The electrochemical behavior of dopamine(DA), uric acid(UA) and AA was investigated, respectively. The results showed that the resulting modified electrode exhibited excellent electrocatalytic activity toward the electrooxidation of DA and UA and had superior selectivity for the determination of DA, UA in the presence of AA. Under the optimum conditions, the liner calibration curves of 1.0 × 10-8 ~ 5.0 × 10-6 mol·L-1 and 1.0 × 10-8 ~ 5.0 × 10-6 mol·L-1 with the detection is 0.5 × 10-9 mol·L-1 and 0.5 × 10-9 mol·L-1(3sb) was obtained for DA and UA, respectively.2. Benefiting from the advantages of nano gold and graphene in electrochemical sensing, a nano gold/grphene composite film modified electrode(Au NPs/GR/GCE) was fabricated by using electrochemical methods. The electrochemical behavior of isoniazid(INZ) on the this modified electrode was also investigated carefully. The results showed that the resulting modified electrode had high electrocatalytic activity and good selectivity for the electro-oxidation of isoniazid. Based on this, cyclic voltammetry was used to determine the concentration of isoniazid in real sample. Under optimum conditions, Oxidation peak potential of 0.31 V, the linear range was 1.0 × 10-7 mol ·L-1 ~ 1.0 × 10-4 mol·L-1 with the detection limit of 5.0 × 10-8 mol·L-1(3sb).3. A multi-walled carbon nanotube and graphene composite film modified electrode(MWCNT-GR/GCE) was fabricated by dropping methods. The electrochemical behavior of isoniazid(INZ) on this modified electrode was investigated carefully. The results showed that the resulting modified electrode exhibited excellent electrocatalytic activity toward the electrooxidation of INZ. Under the optimal conditions, Oxidation peak potential of 0.35 V, the linear range for determination of INZ by LSV was 1.0 × 10-7 mol·L-1 ~ 1.0 × 10-4 mol·L-1 with the detection limit of 5.0 × 10-8 mol·L-1(3sb). Finally, this method was successfully employed to determine isoniazid in injection.4. A multi-walled carbon nanotubes and graphene composite film modified electrode(GR/MWCNT/GCE) was fabricated by two steps. Firstly, a multi-walled carbon nanotubes film modified electrode(MWCNT/GCE) was fabricated by using dipping method. Then GR/MWCNT/GCE composite film modified electrode was prepared with electrochemical deposition technique from a graphene oxide containing solution. The electrochemical behavior of nitrite on this modified electrode was investigated carefully. The results showed that the resulting modified electrode exhibited excellent electrocatalytic activity toward the electrooxidation of nitrite. Under the optimal conditions, the linear range for determination of nitrite by DPV was 1.0 × 10-7 mol·L-1 ~ 1.7×10-3 mol·L-1 with the detection limit of 5.0 × 10-8 mol·L-1(3sb). The proposed method was applied to detect nitrite in real samples with satisfactory results.5. A nano-gold, multi-walled carbon nanotube and graphene composite film modified electrode(Au/GR/MWCNT/GCE) was fabricated by electrochemical deposition method. The electrochemical behavior of bisphenol A(BPA) on this modified electrode was investigated carefully. The results showed that the resulting modified electrode exhibited excellent electrocatalytic activity toward the electrooxidation of AR. Under the optimal conditions, the linear range for determination of BPR by CV was 5.0 × 10-9 mol·L-1 ~ 2.0 × 10-5 mol·L-1 with the detection limit of 2.5 × 10-9 mol·L-1(3sb). Finally, this method was successfully employed to determine isoniazid in plastic bag.