Department of Analytical Chemistry, Institute of Chemistry, State University of São Paulo, Araraquara, SP, Brazil; Department of Chemistry, Federal University of São Carlos, Rod. Washington Luís km 235, São Carlos, SP, Brazil.
Department of Chemistry, Federal University of São Carlos, Rod. Washington Luís km 235, São Carlos, SP, Brazil.
Talanta. 2021 Jan 15;222:121539. doi: 10.1016/j.talanta.2020.121539. Epub 2020 Aug 18.
The present study reports the development of graphite pencil electrode modified with palladium nanoparticles (PdNPs) and its application as an electrochemical sensor for the simultaneous detection of direct yellow 50, tryptophan, carbendazim and caffeine in river water and synthetic urine samples. The combination involving the conductive surface of the graphite pencil electrode (GPE) and the enlargement of the surface area caused by the use of palladium nanoparticles (PdNPs) led to the improvement of the analytical performance of the proposed device. The surface of the GPE-PdNPs was characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The charge transfer kinetics of the electrode was evaluated based on the electrochemical analysis of the potassium ferricyanide redox probe. Using square wave voltammetry (SWV), well-defined and fully resolved anodic peaks were detected for the analytes, with peak-to-peak potential separation not less than 200 mV. Under optimised conditions, the following linear range concentrations were obtained: 0.99-9.9 μmol L for direct yellow 50; 1.2-12 μmol L for tryptophan; 0.20-1.6 μmol L for carbendazim; and 25-190 μmol L for caffeine. The sensor showed good sensitivity, repeatability, and stability. The device was successfully applied for the determination of analytes in urine and river water samples, where recovery rates close to 100% were obtained. Due to its low cost and reusability by simple polishing, the sensor has strong potential to be used as an electrochemical sensor for the determination of different analytes.
本研究报告了一种修饰有钯纳米粒子（PdNPs）的石墨铅笔电极的开发及其作为电化学传感器在河水和合成尿样中同时检测直接黄 50、色氨酸、多菌灵和咖啡因的应用。石墨铅笔电极（GPE）的导电表面与钯纳米粒子（PdNPs）的表面积增大的结合导致了所提出的装置的分析性能得到改善。通过扫描电子显微镜（SEM）和能量色散光谱（EDS）对 GPE-PdNPs 表面进行了表征。根据铁氰化钾氧化还原探针的电化学分析，评估了电极的电荷转移动力学。使用方波伏安法（SWV），对分析物进行了检测，得到了定义良好且完全分辨的阳极峰，峰-峰电位分离不小于 200 mV。在优化条件下，得到以下线性范围浓度：直接黄 50 的浓度为 0.99-9.9 μmol L；色氨酸的浓度为 1.2-12 μmol L；多菌灵的浓度为 0.20-1.6 μmol L；咖啡因的浓度为 25-190 μmol L。该传感器具有良好的灵敏度、重复性和稳定性。该装置成功地应用于尿液和河水样品中分析物的测定，得到了接近 100%的回收率。由于其成本低且可通过简单的抛光进行重复使用，该传感器具有作为电化学传感器用于测定不同分析物的强大潜力。
