Nassef Hossam M, Civit Laia, Fragoso Alex, O'Sullivan Ciara K
Department of Chemical Engineering, Nanobiotechnology and Bioanalysis Group, Universitat Rovira I Virgili, Tarragona, Spain.
Analyst. 2008 Dec;133(12):1736-41. doi: 10.1039/b808499h. Epub 2008 Sep 27.
Electrode modification by electrochemical reduction of diazonium salts of different aryl derivatives is useful for catalytic, analytical and biotechnological applications. A simple and sensitive method for the electrocatalytic detection of ascorbic acid using disposable screen-printed carbon electrodes modified with an electrografted o-aminophenol film, via the electrochemical reduction of its in situ prepared diazonium salts in aqueous solution, is presented. The performance of two commercial SPEs as substrates for grafting of diazonium films has been compared and the grafting process optimized with respect to deposition time and diazonium salt concentration, with the modified surfaces being characterised using cyclic voltammetry. The functionalised screen-printed electrodes demonstrated an excellent electrocatalytic activity towards the oxidation of ascorbic acid shifting the overpotential from 298 and 544 mV to 160 and 244 mV, respectively vs. Ag/AgCl. DC amperometric measurements were carried out for the quantitative determination of ascorbic acid using the modified electrodes. The catalytic oxidation peak current was linearly dependent on the ascorbic acid concentration in the range of 2-20 microM, with a correlation coefficient 0.998, and a limit of detection of 0.86 microM was obtained with an excellent reproducibility (RSD% = 1.98, n = 8). The functionalised screen-printed electrodes exhibited notable surface stability, and were used as a simple and precise disposable sensor for the selective determination of ascorbic acid.
通过对不同芳基衍生物的重氮盐进行电化学还原修饰电极，可用于催化、分析和生物技术应用。本文提出了一种简单灵敏的方法，即使用经电嫁接邻氨基酚膜修饰的一次性丝网印刷碳电极，通过其在水溶液中原位制备的重氮盐的电化学还原，对维生素C进行电催化检测。比较了两种商用丝网印刷电极作为重氮盐膜接枝底物的性能，并针对沉积时间和重氮盐浓度对接枝过程进行了优化，使用循环伏安法对修饰表面进行了表征。功能化的丝网印刷电极对维生素C的氧化表现出优异的电催化活性，相对于Ag/AgCl，过电位分别从298和544 mV移至160和244 mV。使用修饰电极进行直流安培测量以定量测定维生素C。催化氧化峰电流在2-20 microM范围内与维生素C浓度呈线性相关，相关系数为0.998，检测限为0.86 microM，重现性良好（RSD% = 1.98，n = 8）。功能化的丝网印刷电极表现出显著的表面稳定性，并用作一种简单精确的一次性传感器，用于选择性测定维生素C。
