Department of Inorganic Chemistry, University of Madras, Guindy Campus, Chennai, 600 025, India.
Institute of Nano Electronic Engineering, Universiti of Malaysia Perlis, 01000, Kangar, Perlis, Malaysia.
Mikrochim Acta. 2019 Jan 7;186(2):54. doi: 10.1007/s00604-018-3117-7.
Differential pulse voltammetry (DPV) was employed for the determination of caffeic acid (CA) in acidic solutions by using a glassy carbon electrode (GCE) modified with a chitosan-protected nanohybrid composed of carbon black and reduced graphene oxide. Electrochemical impedance spectroscopy and cyclic voltammetry were utilized to study the interfacial electron transfer on the modified GCE. Cyclic voltammetry shows that CA exhibits a reversible redox reaction with an oxidation peak at + 0.30 V (vs. Ag/AgCl) and a reduction peak at + 0.24 V in pH 3.0 solution at a scan rate of 50 mV·s. Under the optimized experimental conditions, the response to CA is linear in 0.3× 10 to 57.3 × 10 M concentration range. The limit of detection is 0.03 × 10 M (at an S/N ratio of 3), and the electrochemical sensitivity is 5.96 μA∙ μM∙cm. This sensor for CA displays better sensitivity and a response over a wider concentration range. It was applied to the determination of CA at trace levels in various (spiked) wine samples. Graphical abstract Schematic presentation of a sensitive electrochemical method for the quantitative detection of caffeic acid using chitosan protected carbon black and reduced graphene oxide. It can be used for the quantitative detection of caffeic acid in wine samples.
差分脉冲伏安法（DPV）被用于通过使用壳聚糖保护的由炭黑和还原氧化石墨烯组成的纳米杂化体修饰的玻碳电极（GCE）来测定酸性溶液中的咖啡酸（CA）。电化学阻抗谱和循环伏安法被用于研究修饰 GCE 上的界面电子转移。循环伏安法表明，CA 在 pH 3.0 溶液中以 50 mV·s 的扫描速率显示出具有 + 0.30 V（相对于 Ag/AgCl）氧化峰和 + 0.24 V 还原峰的可逆氧化还原反应。在优化的实验条件下，CA 的响应在 0.3×10 到 57.3×10 M 的浓度范围内呈线性。检测限为 0.03×10 M（信噪比为 3），电化学灵敏度为 5.96 μA·μM·cm。这种 CA 传感器具有更高的灵敏度和更宽的浓度响应范围。它被用于测定各种（加标）葡萄酒样品中的痕量 CA。
