A sensitive electrochemical sensor featuring novel composites of gold and carbon nanocomplexes alongside a polymerized amino acid was developed for the determination of uric acid (UA) and dopamine (DA) concentrations in both buffer and human urine sample solutions. The sensor was fabricated by electropolymerization of l-methionine (l-Met) followed by coating of carbon nanotube-graphene complexes and electrodeposition of gold nanoparticles on a screen printed carbon electrode surface. The electrode surfaces were characterized by field emission scanning electron microscopy and energy dispersive spectroscopy, and the electrochemical properties were investigated by cyclic voltammetry and differential pulse voltammetry. Linear ranges of 0.05-3 μM and 1-35 μM with limits of detection of 0.0029 and 0.034 μM were achieved for DA and UA, respectively. In addition, the developed sensor was applied for the analysis of native UA and DA concentrations in undiluted and diluted human urine samples. The UA analysis results were compared to those obtained using high performance liquid chromatography and a fluorometric assay kit while the DA analysis results were compared to those obtained using liquid chromatography-tandem mass spectrometry.

中文翻译：

---

丝网印刷碳电极上的聚（1-甲硫氨酸），碳纳米管-石墨烯络合物和金纳米颗粒的纳米复合材料，用于人尿液中多巴胺和尿酸的电化学分析。

开发了一种灵敏的电化学传感器，其特征在于金和碳纳米复合物的新型复合物以及聚合的氨基酸，用于测定缓冲液和人尿样品溶液中的尿酸（UA）和多巴胺（DA）浓度。传感器是通过对L-蛋氨酸（l-Met）进行电聚合，然后涂覆碳纳米管-石墨烯络合物，以及将金纳米颗粒电沉积在丝网印刷的碳电极表面上而制成的。通过场发射扫描电子显微镜和能量色散光谱对电极表面进行表征，并通过循环伏安法和差分脉冲伏安法研究电化学性能。DA和UA的线性范围分别为0.05-3μM和1-35μM，检出限为0.0029和0.034μM。此外，开发的传感器还用于分析未稀释和稀释的人类尿液样品中天然UA和DA的浓度。将UA分析结果与使用高效液相色谱和荧光分析试剂盒获得的结果进行比较，而将DA分析结果与使用液相色谱-串联质谱法获得的结果进行比较。