The Preparation Of Functionaiized Graphene Modified Electrode Sensors And Application In Electroanalytical Chemistry

In this paper, functionalized graphene and its composites were used as modified electrode materials. Then several electrochemical sensors were fabricated based on the modified electrodes for sensitivity determination of real samples. The major contents are described as follows:1. The poly (diallyldimethylammonium chloride)(PDDA) functionalized graphene nanosheets (PDDA-G) were prepared. Simultaneous determination of catechol (CC) and hydroquinone (HQ) were investigated by cyclic voltammetry (CV) and square wave voltammetry (SWV) based on PDDA-G modified glassy carbon electrode (PDDA-G/GCE). The modified electrode showed excellent sensitivity and selectivity towards the two dihydroxybenzene isomers. Under the optimized conditions, the PDDA-G/GCE showed the wide linear range and low detection limits to CC and HQ respectively. The proposed method was applied to simultaneously determine CC and HQ in water samples with satisfactory results.2. Au-PDDA-G nanocomposites were rapidly synthesized via a one-step method, and characterized by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy.An electrochemical sensor based on Au-PDDA-G was fabricated for the sensitive detection of alkannin. The nanocomposite was characterized carefully. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to investigate the electrochemical behaviors of alkannin on the Au-PDDA-G composite film modified GCE. The linear range of alkannin was from5.0to300nmol/L with a detection limit of1.4nmol/L (S/N=3). Moreover, the sensor could be used for the detection of alkannin in real samples with satisfactory results.3. Arginine (Arg) functionalized graphene (Arg-G) nanocomposite was produced successfully by an environment-friendly method, and the morphology of the nanocomposite was characterized by TEM, Raman spectra etc. Based on Arg-G nanocomposite, a green electrochemical sensor was fabricated for sensitive detection of bisphenol A (BPA). Under the optimized conditions, the oxidation peak current was proportional to BPA concentration in the range between5.0nmol/L and40.0μmol/L with the correlation coefficient of0.9986and the detection limit of1.1nmol/L (S/N=3). The proposed sensor was successfully employed to determine BPA in real plastic products and the recoveries were satisfactory.