Simultaneous determination of uric acid, xanthine and hypoxanthine at poly(pyrocatechol violet)/functionalized multi-walled carbon nanotubes composite film modified electrode

A sensitive and selective electrochemical method was developed for simultaneous determination of uric acid (UA), xanthine (XA) and hypoxanthine (HX) based on a poly (pyrocatechol violet)/carboxyl functionalized multi-walled carbon nanotubes composite film modified electrode. The preparation and basic electrochemical performance of the novel composite film modified glassy carbon electrode were investigated in details. The electrochemical behaviors of UA, XA and HX at the modified electrode were studied by cyclic voltammetry. The results showed that this new electrochemical sensor exhibited excellent electrocatalytic activity towards the oxidation of the three analytes. The mechanism of catalysis was discussed. The anodic peaks of the three species were well defined with lowered oxidation potential and enhanced oxidation peak currents, so the modified electrode was used for simultaneous voltammetric measurement of UA, XA and HX by differential pulse voltammetry. Under the optimum conditions, the detection limits were 0.16 μmol L−1 for UA, 0.05 μmol L−1 for XA and 0.20 μmol L−1 for HX, respectively (S/N of 3). The proposed method has been successfully applied to simultaneous determination of UA, XA and HX in human serum samples.

Simultaneous determination of Uric acid (UA), xanthine (XA) and hypoxanthine (HX) in human serum sample using a novel poly(pyrocatechol violet)/ carboxyl functionalized multi-walled carbon nanotubes composite film modified electrode. (a) Blank serum sample; (b) serum sample spiked with 8.0 μmol L−1 UA, 5.0 μmol L−1 XA and 5.0 μmol L−1 HX.Figure optionsDownload as PowerPoint slideHighlights
► A novel electrochemical sensor based on poly(pyrocatechol violet)/carboxyl functionalized multi-walled carbon nanotubes composite film.
► Simultaneous determination of uric acid, xanthine and hypoxanthine using this sensor.
► The modified electrode has good stability, sensitivity and selectivity.
► The proposed method can be used in research assays and clinical diagnosis.