Mathematical Model and Circuit Realization to Improve Chronoamperometry

作者:Chen Xu-Hai; Chen Jing-Hua; Pan Hai-Bo; Li Yu-Rong; Du Min*; Lin Xin-Hua
来源:Acta Physico - Chimica Sinica, 2010, 26(11): 2920-2926.
DOI:10.3866/PKU.WHXB20101117

摘要

To overcome the disadvantages of chronoamperometry we report a novel electrochemical method where a peak current is quickly generated for the current vs time curve by changing the waveform of voltage excitation in the working electrode. In particular, we derived a mathematical model to illustrate the principle of this method and it can also be used to demonstrate that the peak current is linear with regards to the concentration of the target substance. Moreover, we developed a device with an improved electrochemical circuit using a control element from control theory to change the waveform of voltage excitation. The improved circuit can detect the peak automatically without a precise sample time. Finally, the device was used to study the electrochemical behavior of K-3[Fe(CN)(6)] and 3,3',5,5'-tetramethylbenzidine (TMB). We show that the method has a better signal to noise ratio and higher sensitivity than chronoamperometry. The obtained peak current is linear with regards to the concentration of the target substance and can be quickly detected without a precise sample time.