In the present paper a voltammetric biosensor based on platinum electrode and polypyrrole / uricase / graphene composite, named Pt-PPy/UOx/Grap has been successfully prepared and validated for uric acid (UA) determination in real samples. The electrochemical behavior has been evaluated by employing cyclic voltammetric. The charge transfer coefficient, α, and the charge transfer rate constant, κs, for electron transfer between PPy/UOx/Grap and Pt were calculated as 0.71, in average, and 48.3 s−1, respectively. Under optimized conditions for the composite (2.5 U mL−1 of UOx, 0.3 mg mL−1 of Grap and 2.9 mmol L−1 of pyrrole) and for the analysis (pH 7.0 in 0.1 mol L−1 phosphate buffer) the method was validated for UA determination at human urine and showed good linearity to UA from 2 up to 24 nmol L−1 (r=0.993) with limits of detection and quantification of 0.541 and 1.805 nmol L−1, respectively. The results obtained for the UA determination at urine presented a relative error lower than 5 %, showing the good performance of the method developed and potential application in UA clinical analysis.

中文翻译：

---

基于聚吡咯/尿酸酶/石墨烯的伏安生物传感器测定尿酸的研制与应用

在本文中，基于铂电极和聚吡咯/尿酸酶/石墨烯复合物的伏安生物传感器，名为 Pt-PPy/UOx/Grap 已成功制备并验证用于实际样品中的尿酸 (UA) 测定。电化学行为已通过使用循环伏安法进行评估。PPy/UOx/Grap 和 Pt 之间的电子转移的电荷转移系数 α 和电荷转移速率常数 κs 分别计算为平均 0.71 和 48.3 s-1。在复合物（2.5 U mL-1 的 UOx、0.3 mg mL-1 的 Grap 和 2.9 mmol L-1 的吡咯）和分析（pH 7.0，在 0.1 mol L-1 磷酸盐缓冲液中）的优化条件下，该方法是经验证可用于人尿中的 UA 测定，并且在 2 至 24 nmol L-1 (r=0. 993)，检测限和定量限分别为 0.541 和 1.805 nmol L-1。尿液中 UA 测定的结果显示出低于 5% 的相对误差，表明所开发方法的良好性能和在 UA 临床分析中的潜在应用。