The determination of gallic acid (GA) and uric acid (UA) is essential due to their biological properties. Numerous methods have been reported for the analysis of GA and UA in various real samples. However, the development of a simple, rapid and practical sensor still remains a great challenge. Here, a carbon paste electrode (CPE) was modified by nanocomposite containing zirconia nanoparticles (ZrO₂NPs), Choline chloride (ChCl) and gold nanoparticles (AuNPs) to construct ZrO₂-ChCl-AuNPs/CPE as electrochemical sensor for the simultaneous electro-oxidation of GA and UA. Characterization was performed by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. The modified electrode was investigated by different methods including electrochemical impedance spectroscopy and cyclic voltammetry. Kinetic parameters such as charge transfer coefficient, standard heterogeneous electron transfer rate constant and other parameters were calculated via voltammetry techniques. Differential pulse voltammetry was used for simultaneous determination of GA and UA applying the ZrO₂-ChCl-AuNPs/CPE electrode. At the optimum conditions, this sensor showed a linear response in the ranges 0.22– 55 and 0.12–55 µM for GA and UA, respectively. In addition, low detection limits of 25 and 15 nM were obtained for GA and UA, respectively. Furthermore, ZrO₂-ChCl-AuNPs/CPE was successfully applied for the independent determination of GA in green tea and fruit juice as well as the simultaneous determination of GA and UA in human urine samples.

没食子酸（GA）和尿酸（UA）的测定因其生物学特性而至关重要。据报道，有许多方法可以分析各种真实样品中的GA和UA。然而，简单，快速和实用的传感器的开发仍然是巨大的挑战。在这里，碳糊电极（CPE）是通过包含氧化锆纳米颗粒（ZrO ₂ NPs），氯化胆碱（ChCl）和金纳米颗粒（AuNPs）的纳米复合材料改性而构建的ZrO ₂-ChCl-AuNPs / CPE作为电化学传感器，用于GA和UA的同时电氧化。通过傅里叶变换红外光谱，X射线衍射，场发射扫描电子显微镜和能量色散X射线光谱进行表征。通过包括电化学阻抗谱和循环伏安法在内的不同方法研究了修饰的电极。动力学参数如电荷转移系数，标准异质电子转移速率常数和其他参数是通过伏安法计算的。使用差示脉冲伏安法同时测定ZrO _2中的GA和UA-ChCl-AuNPs / CPE电极。在最佳条件下，该传感器对GA和UA的线性响应分别在0.22–55和0.12–55 µM的范围内。此外，GA和UA的检测限分别低至25和15 nM。此外，ZrO ₂ -ChCl-AuNPs / CPE已成功用于绿茶和果汁中GA的独立测定，以及人尿液样品中GA和UA的同时测定。