Electrochemical Detection Technology At Zero Potential

In this dissertation, several new ways to construct biamperometric detection system have been proposed, such as the use of two different electrodes, the couples of one reversible and one irreversible electrode process and of two reversible electrode processes. Furthermore, the application of the method has been investigated.This dissertation includes the works in the following aspects.1. A simple flow-injection irreversible biamperometric method for the determination of dopamine hydrochloride injection has been described. The system can run without the application of an external potential. The oxidation current of dopamine dydrochloride shows linear relationship from 0.8μg /mL to 160μg /mL with a detection limit of 0.2μg /mL. The reproducibility of the method is testified by a relative standard deviation (R.S.D.) of 2.86 % for 14 reduplicate determination of 80 μg /mL dopamine hydrochloride. The method offers the advantages of simplicity, high efficiency (80 samples /h), and good selectivity, and is suitable for the determination of dopamine hydrochloride injection.2. An original, simple and sensitive flow-injection irreversible biamperometric method for the determination of chlorpromazine hydrochloride in pure form or in pHarmaceutical is described. The method deponds on the electrochemical oxidation of chlorpromazine at a pretreated platinum electrode and the reduction of permanganate at another pretreated platinum electrode. By coupling the two independent and irreversible electrode processes, the biamperometric detection scheme has been established. Under the applied potential difference of 0 V, in the 0.05mol/L sulfuric acid, chlorpromazine hydrochloride can be determined over the range 1.0×10^-5 to 1.0×10^-3 mol L^-1with a sampling frequency of 80 samples per hour. The detection limit for chlorpromazine hydrochloride is 2.0×10^-6 mol L^-1 and the RSD for 19 replicate determinations of 2.0×10^-4mol/L chlorpromazine hydrochloride is 2.23%. The proposed method was applied to the analysis of chlorpromazine hydrochloride in chlorpromazine hydrochloride tablets and injections with satisfactory results.3. A novel method for the direct determination of acetaminopHen is developed by...