Voltammetric Sensing of Uric Acid and Ascorbic Acid with Poly (p-toluene sulfonic acid) Modified Electrode

Glassy carbon electrode (GCE) is modified with electropolymerized films of p-toluene sulfonic acid (pTSA). This polymer (pTSA) modified electrode is used to electrochemically detect uric acid (UA) in the presence of ascorbic acid (AA) and shows an excellent electrocatalyticl effect on the oxidation of UA and AA by cyclic voltammetry (CV). In differential pulse voltammetric measurements (DPV), the polymer (pTSA) modified electrode could separate the oxidation peak potentials of UA and AA present in the same solution by about 300 mV though the bare electrode gave a single broad response. A successful elimination of the fouling effect by the oxidized product of AA on the response of UA has been achieved at the polymer (pTSA) modified electrode. The detection limit of UA in the presence of AA at millimolar level was 5.0 x 10(-7) M. The modified electrode exhibits the stable and sensitive response to UA.