Study On The Preparation And Application Of Poly(3,4-ethylened-ioxythiophene)-based Nanocompo-sites Modified Electrodes

In this paper, the conductive polymer poly(3,4-ethylenedioxythiophene)(PEDOT)-based composite material modified carbon past electrodes were prepared andcharacterized mainly using electrochemical methods. The electrochemical behaviors ofseveral small molecules were researched on the prepared electrodes and theelectrochemical analysis methods of related molecules were established. PEDOT/CNT,PEDOT/PSS, PEDOT/DNA composite film modified electrodes were successfullysynthesized via chemical oxidation or electrochemical method. These materials and themodified electrodes were characterized and analysised by scanning electronmicroscopy (SEM), the AC impedance (EIS), cyclic voltammetry (CV), differentialpulse voltammetry (DPV), chronoamperometry (i-t) and other methods. What’s more,the prepared modified electrodes were used to investigate the electrochemical behavior,the systems analysis conditions, the analysis validation of the actual sample and theinterference experiments of several kinds of small molecules. The main contents aresummarized as below:(1) PEDOT/CNT nanocomposites were synthesized via FeCl3chemical oxidationmethod, and characterized by scanning electron microscopy. Cyclic voltammetryresults indicated that the PEDOT/CNT nanocomposites modified carbon past electrodeexhibited well electrocatalytic activity to the oxidation of HQ and reduction of NB.DPV results demonstrated that the modified electrode displayed a quick response withlinear range of1.1-125μmol/L and associated with a detection limit of0.3μmol/L forHQ. Amperometric response results indicated that the calibration curves for NB wasobtained over the range of0.25–43μmol/L, and the detection limit was83nmol/L. In addition, the PEDOT/CNT/CPE showed good selectivity for HQ and NB detection inthe presence of several interfering species and can be applied to determine HQ and NBin real samples with satisfactory results.(2) PEDOT/CNT and PEDOT/PSS nanocomposites were synthesized viaelectrochemical method. The PEDOT/CNT morphology was characterized byscanning electron microscopy. Cyclic voltammetry was used to evaluate theelectrochemical response of a carbon past electrode (CPE) modified with thenanocomposite towards dopamine (DA). Compared to the bare CPE, the CNTnanoparticles modified electrode and the PEDOT/PSS modified electrode, thePEDOT/CNT nanocomposites modified electrode displays high electrocatalyticactivity. Under optimal conditions, DPV response results indicated that theconcentration of DA in the range from0.1to20μmol/L, with a detection limit of20nmol/L (S/N=3). The modified electrode shows excellent selectivity and highsensitivity even in the presence of high concentration of ascorbic acid (AA).(3) PEDOT/DNA composite film modified electrode was successfully prepared via afacile one-step electrochemical method and used for determination of DA.Electrochemnical measurement indicates that PEDOT/DNA nanocomposites modifiedelectrode exhibits an excellent electrochemical activity of DA. Under the optimizedconditions, the modified electrode was successfully employed for the voltammetricdetermination of DA with a low detection limit and wide linear range.