The Preparation Of Graphene And Polymer Film Modified Glass Carbon Electrodes And Their Application In Medicine Analysis

In this thesis, several components of medicine were analyzed by modified electrodes such as graphene oxide copolymerized baicalin modified glassy carbon electrode, Poly-baicalin Modified Glassy Carbon Electrode andβ-Cyclodextrin incorporated graphene modified electrode. The major contents are described as follows:Part 1:The paper described the preparation, characterization of graphene oxide and graphene oxide copolymerized Baicalin (GO/PBAI) modified glassy carbon electrode (GCE). Then the modified electrode was successfully employed for the simultaneous determination of dopamine (DA), ascorbic acid (AA) and uric acid (UA). The GO/PBAI modified GCE exhibited well-defined and-separated oxidation peaks in diffential pulse voltammetry (DPV) imagine, DA, AA and UA in 0.1M phosphate buffer solution (PBS pH=5.0). The separations of anodic peak potential of DA, AA and UA on GO/PBAI/GCE were 264mV,60.0 mV and 428 mV respectively. Under the optimum conditions, differential pulse voltammetry (DPV) was used for the detection of DA, AA and UA, we found that the anodic peak current and concentration had perfect linear relationship, the calibration curves for DA, AA and UA were obtained in the range of 2×10-6～8×10-5mol/L, 1×10-6～1.2×10-4mol/Land 3×10-7～4.5×10-5mol/L respectively. The low detection limit of DA, AA and UA was 5×10-7mol/L,3×10-6mol/L and 1×10-7mol/L respectively. This new modified electrode had good long-term stability and reproducibility with relative standard deviations (R.S.D.) of less than 5% for three chemical reagents.In addition, the new analysis method was used for the determination of DA in dopamine hydrochloride injections, AA in VC injections and UA in human urine samples respectively which had satisfactory results.Part2:An electrochemical modified electrode based on the electrocatalytic activity ofβ-Cyclodextrin (β-CD) incorporated chemical reduced graphene (CRG) was prepared, which was used to sensitive detection of rutin. The electrochemical behaviors of rutin onβ-CD/CRG modified glassy carbon electrode (GCE) were investigated by cyclic voltammetry and differential pulse votammetry respectively. The electrochemical experimental results showed that theβ-CD/CRG modified GCE exhibited excellent electrocatalytic activity to rutin. A linear calibration plot was obtained by differential pulse voltammetry (DPV) covering the range from 4.0×10-8 to 1.0×10-4 mol L-1 with a detection limit of 9.7x10-9 mol L-1, and the relative standard deviation (RSD%) was lower than 5% (N=21). The method was successfully applied to detect rutin content in the tablets without previous separation.Part 3:A novel polymerized film of baicalin (BAI) was prepared on the surface of glassy carbon electrode (GCE) by electro-polymerization. The characterization of poly-BAI film was investigated by atomic force microscopy (AFM). The poly-BAI modified GCE exhibited excellent electro catalytic activity towards the oxidations of BAI in 0.1 mol/L phosphate buffer solution (pH 3.0). Then the modified electrode was successfully used to determine baicalin (BAI) by differential pulse voltammetry (DPV) method. Under the optimal conditions, a good linear relationship between the anodic peak current and concentration of baicalin was obtained in the range of 3×10-8～1×10-5mol/L, with the detection limit of 3×10-9mol/L(S/N=3). The modified electrode was used to determination of BAI in human urine samples and achieved satisfactory results.