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

Preparation of DNA/Poly(34-ethylenedioxythiophene) Composite Film Modified Glassy Carbon Electrode and Its Application to the Study on Electrochemical Behavior and Determination of Nitrite

采用恒电流和电沉积两步法制备了脱氧核糖核酸-聚（3,4-乙烯基二氧噻吩）（DNA-PEDOT）复合膜修饰玻碳电极。用电化学阻抗法（EIS）和循环伏安法（CV）表征了不同修饰电极的修饰可行性和表面的电子传递能力。结果表明,DNA可以牢固地结合在PEDOT膜上,并能改善PEDOT膜的性质。研究了NO2-在DNA-PEDOT修饰电极上的电化学行为,提出了一种新的检测NO2-的电化学方法。在0.1 mol/L pH7.0的磷酸盐缓冲溶液（PBS）中,NO2-在DNA-PEDOT修饰电极上于0.88 V左右出现1个较好的氧化峰,考察了该氧化峰的性质及其影响因素。示差脉冲伏安法（DPV）的结果表明,NO2-的DPV氧化峰电流与其浓度在0.3-1.0、1.0-20、20-100μmol/L 3个范围内呈良好的线性关系,检出限（S/N=3）为60 nmol/L,并考察了可能存在的干扰物质对测定的影响。结果显示,该复合膜修饰电极对NO2-的检测具有良好的稳定性和选择性。将其用于实际样品的检测,结果满意。

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.