Stimulate Determination Of Ascorbic Acid And Dopamine At Polyaniline Modified Electrode

Chemically modified electrodes (CME) are widely used in testing biomolecules.Variety functional groups of the modified materials at the CME surface can helpcatalyze and/or enrich the analyte nearby the electrodes, which will improve theselectivity and sensitivity of CME. Polyaniline (PANI) has the advantages over otherchemical materials on its cheap raw materials, simple synthesis, high conductivity,unique protonic acid doping/dedoping process and reversible redox reactions. Here,polyaniline nanomaterials modified platinum electrodes are prepared and used tosimulate determination ascorbic acid (AA) and dopamine（DA）electrochemically.PANI nanomaterials are synthesized by chemical oxidation method with potassiumiodate as the oxidant. PANI-NF/Pt electrodes were prepared by depositing PANInanomaterials dispersion on platinum electrode surface. The effects of experimentalfactors, including potential window, scanning rate, pH of the solution and testtemperature, on the electrochemical activity of PANI-NF/Pt electrodes wereinvestigated by cyclic voltammetry (CV) tests. Experimental results show that thePANI-NF/Pt electrodes show good electrochemical activity with the potential windowfrom0.000to0.650V vs. SCE, in1mol/L HCl solution.The PANI-NF/Pt electrodes were used to simulate determination AA and DA andthe affecting factors are studied by linear scan voltammetry（LSV）and square wavevoltammetry (SWV) methods. The experimental results show that the signal ofdopamine at the PANI-NF/Pt electrodes is diffusion controlled, while that of AA isadsorption controlled. Furthermore, the determination linear range of AA is from26.05μmol/L to213.16μmol/L, and the detection limit is6.21μmol/L (signal tonoise ratio S/N=3), while that for DA is from62.5μmol/L to603.0μmol/L and33.3μmol/L respectively. The PANI-NF/Pt electrodes can be used to simulatedetermination AA and DA quickly and accurately with a good separation. And thismethod may be applied to determination AA and DA in blood, food and biologicalagents.