DNA/聚（3, 4-乙烯基二氧噻吩）修饰电极的制备及其用于亚硝酸根的电化学行为及测定研究

A novel DNA-poly (3, 4-ethylenedioxythiophene) composite film modified glassy carbon electrode (DNA-PEDOT/GCE) was prepared by constant current electrolysis and electro-deposition. The modified electrode was characterized by the methods of electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The results showed that the DNA could be immobilized on the PEDOT film firmly and improved the property of PEDOT. The electrochemical behavior of nitrite at the DNA-PEDOT/GCE was investigated and the electrochemical method for the determination of nitrite was established. The experimental results indicated that the composite film modified electrode could combine the advantages of PEDOT and DNA, and were propitious to the oxidation of nitrite. In 0.1 mol/L pH 7.0 phosphate buffer solution (PBS), the anodic peak currents of differential pulse voltammograms (DPVs) were linear with the nitrite concentration in three intervals, viz. 0.3-1.0 μmol/L, 1.0-20 μmol/L and 20-100 μmol/L, and the detection limit (S/N=3) was 60 nmol/L. Moreover, the interferences were effectively diminished. This proposed composite film modified electrode also showed excellent reproducibility and stability, and was applied in the detection of nitrite in real sample with satisfatory results.