Institute of Chemistry, São Paulo State University (UNESP), Araraquara 14801-970, SP, Brazil.
National Institute for Alternative Technologies of Detection, Toxicological Evaluation and Removal of Micropollutants and Radioactives (INCT-DATREM), Araraquara 14801-970, SP, Brazil.
Biosensors (Basel). 2023 Jun 29;13(7):690. doi: 10.3390/bios13070690.
The present study reports the development and application of a flow injection analysis (FIA) system for the simultaneous determination of uric acid (UA) and caffeine (CAF) using cathodically pretreated boron-doped diamond electrode (CPT-BDD) and multiple-pulse amperometry (MPA). The electrochemical profiles of UA and CAF were analyzed via cyclic voltammetry in the potential range of 0.20-1.7 V using 0.10 mol L HSO solution as supporting electrolyte. Under optimized conditions, two oxidation peaks at potentials of 0.80 V (UA) and 1.4 V (CAF) were observed; the application of these potentials using multiple-pulse amperometry yielded concentration linear ranges of 5.0 × 10-2.2 × 10 mol L (UA) and 5.0 × 10-1.9 × 10 mol L (CAF) and limits of detection of 1.1 × 10 and 1.3 × 10 mol L for UA and CAF, respectively. The proposed method exhibited good repeatability and stability, and no interference was detected in the electrochemical signals of UA and CAF in the presence of glucose, NaCl, KHPO, CaCl, urea, Pb, Ni, and Cd. The application of the FIA-MPA method for the analysis of environmental samples resulted in recovery rates ranging between 98 and 104%. The results obtained showed that the BDD sensor exhibited a good analytical performance when applied for CAF and UA determination, especially when compared to other sensors reported in the literature.
本研究报告了一种流动注射分析（FIA）系统的开发和应用，该系统使用阴极预处理的掺硼金刚石电极（CPT-BDD）和多脉冲安培法（MPA）同时测定尿酸（UA）和咖啡因（CAF）。通过循环伏安法在 0.20-1.7 V 的电位范围内分析 UA 和 CAF 的电化学轮廓，使用 0.10 mol L HSO 溶液作为支持电解质。在优化条件下，在 0.80 V（UA）和 1.4 V（CAF）处观察到两个氧化峰；使用多脉冲安培法在这些电位下应用得到的浓度线性范围分别为 5.0×10-2.2×10 mol L（UA）和 5.0×10-1.9×10 mol L（CAF），UA 和 CAF 的检测限分别为 1.1×10 和 1.3×10 mol L。所提出的方法表现出良好的重复性和稳定性，在存在葡萄糖、NaCl、KHPO、CaCl、尿素、Pb、Ni 和 Cd 的情况下，UA 和 CAF 的电化学信号中没有检测到干扰。FIA-MPA 方法在环境样品分析中的应用得到了回收率在 98%至 104%之间的结果。结果表明，BDD 传感器在用于 CAF 和 UA 测定时表现出良好的分析性能，特别是与文献中报道的其他传感器相比。
