A pre-anodized inlaying ultrathin carbon paste electrode for simultaneous determination of uric acid and folic acid

A pre-anodized inlaying ultrathin carbon paste electrode (PAIUCPE) was prepared by electrochemical pretreatment. The scanning electron microscope (SEM) was applied to characterize the surface morphology of PAIUCPE and the performance of the electrode was characterized by cyclic voltammetry (CV). The results indicated that PAIUCPE displayed excellent electrocatalysis for the oxidation of uric acid (UA) and folic acid (FA). The separated extent between the two oxidation peaks of UA and FA was 324 mV, which was enough for the simultaneous detection. In 0.10 mol/L PBS (pH 6.00), the linear scan voltammetry (LSV) response of UA and FA increased linearly with the concentration in the range of 4.0 × 10−6–3.5 × 10−4 mol/L and 3.0 × 10−6–2.0 × 10−4 mol/L with the detection limits of 1.1 × 10−7 mol/L and 1.5 × 10−7 mol/L, respectively. It was successfully used to determine UA and FA in human urine simultaneously.

In 0.10 mol/L PBS (pH 6.00), oxidation reaction occurred at the PAIUCPE owing to uric acid (UA) loss electrons, while oxygen dissolved in the feed was reduced at the platinum electrode. Furthermore, the effect of electrode reaction at the platinum electrode on that of working electrode is detailedly discussed.Figure optionsDownload as PowerPoint slideHighlights
► The simultaneous determination of UA and FA is achieved at the PAIUCPE.
► The effect of reaction at the Pt electrode on that of working electrode is discussed.
► The effect of pH on peak currents is detailedly explained for the first time.