| Chemically modified electrodes continue to be a field of exciting research since the middle of the seventies. Many techniques have been developed for preparation of modified surfaces. The significant progress has come in polymer film electrodes. In recent years, polymer modified electrodes have attracted a great attention as polymeric film has good stability and reproducibility. In this dissertation, new type of polymer-modified electrodes used for the electrochemical detection of neurotransmitters were fabricated and characterized. The contents and results were summarized and presented as follows: 1. A poly (acridine red) modified glassy carbon electrode (GCE) was prepared by electropolymerization. The modified electrode was proved to have electrocatalytical effect on the electrochemical response of dopamine (DA). The results showed that the DA anodic peak current and the concentration had a linear relationship in the range of 1.0×10-7 1.0×10-4 mol L-1. The detection limit (S/N=3) was 1.0×10-9 mol L-1. The proposed method showed good sensitivity, reproducibility, stability and recovery for the determination of DA. The interference of ascorbic acid (AA) could be efficiently eliminated. 2. o-aminobenzoic acid (o-ABA) film is deposited on GCE by electropolymerization. The polymeric film shows an excellent electrocatalytical activity on oxidation of DA. Difference pulse voltammetry (DPV) was performed to determine DA in an excess of AA. The oxidation peak potentials of DA and AA recorded are 144 mV and –52 mV, respectively when they coexist. In pH 7.0 PBS, the anodic peak current of DA increases linearly over two concentration intervals, viz., 1.0×10-7 1.0×10-5 mol L-1 and 1.0×10-5 2.0×10-4 mol L-1. The result showed that modified electrode could be used for simultaneous determination of DA and AA. 3. CV, DPV and amperometric curve described the determinaton of DA on the poly aminobenzene sulfonic acid (p-ABSA) modified GCE. Polymer film showed excellent electrocatalytic activity for the oxidation of DA and AA. In DPV recording, the peak potentials of DA and AA are 196 mV and –8 mV, respectively. In pH 7.0 PBS, the anodic peak current increases linearly over three concentration intervals of DA, viz., 1.0×10-7 1.0×10-6 mol l-1, 1.0×10-6 1.0×10-5 mol l-1 and 1.0×10-5 1.0×10-4 mol l-1, and the detection limit (S/N = 3) is 2.0×10-8 mol l-1. 4. Poly (amidosulfonic acid) modified GCE was used for the detection of epinephrine (EP) in the presence of AA in PBS of pH 7.0 by cyclic voltammetry (CV). The major difficulty of the overlapped oxidation potential of AA coule be overcome through the distinct attracting interaction between EP cations and the negatively poly (amidosulfonic acid) film. In PBS of pH 7.0, the anodic current increased linearly with the concentration of EP in the range of 1.0×10-7 1.0×10-4 mol L-1. The detect limit (S/N=3) was 1.0×10-8 mol L-1. 5. The electrochemical behavior of EP on poly o-ABA film was studied with electrochemical impedance spectroscopy (EIS), CV and DPV. The modified electrode shows an excellent electrocatalytical activity on EP oxidation. The EP cathodic peak potential shifts negatively with a slope of -53.5 mV/pH. In pH 7.0 PBS, the peak current of EP and the concentration has a linear relationship from 0 to 65 μmol/L by amperometric current –time curve.
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