| The main research work is described as follows:1. Review on detection of environmental organic pollutants by chemically modified electrodeIn chapter one, the types, preparation methods and applicable value of chemically modified electrode has been described briefly, especially in the field of environmental analytical chemistry.2. Fabrication of nano-gold modified electrode (nano-Au/GCE) and research of its propertyWe fabricated a nano-gold modified electrode (nano-Au/GCE) with high sensitivity and selectivity using one step electrochemical deposition method at low potential. By scanning electron microscopy (SEM), we observed the morphology of nano-Au/GCE. And we explored the electrodeposition condition and researched the electrochemical characterization of the nano-Au/GCE. The modified electrode has the advantages of simplicity, convenience, fast response and high controllability.3. Simultaneous voltammetry determination of dihydroxybenzene isomers by Nano-gold modified electrodeA successful elimination of mutual interference between HQ and CC has been achieved at the nano-Au/GCE, and the three dihydroxybenzene isomers can be simultaneously determined without any pretreatment. The nano-Au/GCE has strong electrocatalytic activity for redox behavior of the three dihydroxybenzene compounds, which showed that the peak currents increased significantly. The method has wide linear range and high sensitivity. The linear relationships between the peak height and the concentration are obtained in the range of 2.5×10-6-8.5×10-4 mol/L for HQ, 1.0×10-6-6.5×10-4 mol/L for CC and 3.0×10-6-4.0×10-4 mol/L for RC respectively, with the detection limit of 5.0×10-7mol/L for HQ, 6.5×10-7mol/L for CC and 9.0×10-7mol/L for RC. This method has been applied to the direct determination of the three dihydroxybenzene isomers in artificial wastewater, and the recovery was from 96% to 104%.4.Simultaneous voltammetry determination of nitrophenol isomers by Nano-gold modified electrodeCompared with bare electrode, the nano-Au/GCE can be used to simultaneously determine three nitrophenol isomers without any pretreatment. On the nano-Au/GCE, the oxidation potentials of nitrophenol isomers shifted more negatively and the peak currents considerably enhanced. The oxidation peak potential difference was 92 mV between p-nitrophenol and o-nitrophenol, 142 mV between p-nitrophenol and m-nitrophenol. The linear relationships between the peak height and the concentration are obtained in the range of 1.0×10-5-1.0×10-3mol/L for o-nitrophenol, 1.0×10-6 -6.5×10-4mol/L for m-nitrophenol and 7.5×10-6-2.0×10-3mol/Lfor p-nitrophenol respectively, with the detection limit of 8.0×10-6mol/L for o-nitrophenol, 5.0×10-6mol/L for m-nitrophenol and 8.0×10-6mol/L for p-nitrophenol. This method has been applied to the direct determination of the three nitrophenol isomers in artificial wastewater, and the recovery was 95% -103%.5. Electrochemical sensor for 2,2'-PCB based on NR andβ-CD polymer filmsWe got theβ-CD polymer electrochemical sensor with a convenient and simplemethod of preparing the stable and insolubleβ-CD polymer films by polycondensation with glutaric dialdehyde (GD) on GCE, and developed a new method for determining 2,2'-PCB based on competitive inclusion using NR as a electrochemical probe. The linear range was obtained over the range from 5.0×10-7 mol/L to 6.0×10-6mol/L for 2,2'-PCB, with a detection limit of 3.0×10-7 mol/L, and this electrochemical sensor showed excellent reproducibility, reversibility and selectivity. It has been applied to the determination of 2,2'-PCB in waste water samples with satisfactory results.
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