Electrochemical Synthesis of a Polyaniline Network on a Poly(o-aminophenol) Modified Glassy Carbon Electrode and Its Use for the Simultaneous Determination of Ascorbic Acid and Uric Acid

Abstract

A polyaniline (PAN) network structure was fabricated on a poly(o-aminophenol) (POAP) modified glassy carbon electrode (GCE) by using a three-step electrochemical deposition procedure, and applied to the electro-catalytic oxidation of ascorbic acid (AA) and uric acid (UA). Scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) have been employed to investigate the PAN network structure on a POAP modified GCE (PAN-OAP/GCE), which indicated the formation of a 3-dimensional (3D) non-periodic PAN network with good electrical contract and the maintenance of the electro-activity of PAN in neutral and even in alkaline media. Because of its different catalytic effect towards the electro-oxidation of AA and UA, the PAN-OAP/GCE could resolve the overlapped voltammetric response of AA and UA into two sharp and well-defined voltammetric peaks with both CV and differential pulse voltammetry (DPV), which could be applied for the selective and simultaneous determination of AA and UA in their binary mixture. Under the optimum conditions, the calibration curves for AA and UA were in the range of 2.5 -6200 and 0.5 -450 μmol L -1 with correlation coefficients of 0.998 and 0.998, respectively. The detection limits (S/N = 3) are 1.4 and 0.3 μmol L -1 for AA and UA, respectively. Besides good stability and reproducibility, the PAN-OAP/GCE also exhibited good sensitivity and selectivity. The proposed method has been applied to the simultaneous detection of AA and UA in human urine with satisfactory result.

New Insight into the EC’ Mechanism of Uric Acid Regeneration in the Presence of Ascorbic Acid on a Poly(3,4‐ethylenedioxithiophene) Modified Gold Electrode

“…In such conditions it was therefore not possible to highlight any electrocatalytic effect even if the EC’ mechanism was effective. Some other workers have even ignored the phenomenon although their experimental results (variation of the UA anodic peak current or calibration slope with and without AA) clearly showed it . Only in a few cases no mutual interference was shown, the sensitivity of the modified electrode for UA detection being the same with or without AA .…”

Electrochemical synthesis of a novel purine-based polymer and its use for the simultaneous determination of dopamine, uric acid, xanthine and hypoxanthine

“…UA, XA and HXA are the degradation products of purine metabolism. The typical concentration of UA is 120-450 μmol L −1 in blood and 1.4-4.4 mmol L −1 in urine [5,6]; abnormal UA levels can cause several diseases, such as hyperuricemia, leukemia, and the Lesch-Nyhan syndrome [4,7]. The therapeutic XA level is 10-20 mg mL −1 in blood [8], and the content of XA in blood plasma and urine may provide sensitive indicators of certain pathologic states, especially for xanthinuria.…”

“…Thus, many conducting polymers, such as polythiophene [34,35], polyaniline [7,36,37], polypyrrole [38,39] and polythiazole [40,41] have received a great deal of interest; while, up to now, there is no study for simultaneous detection of DA, UA, XA and HXA by purinebased polymers.…”