| Flow injection analysis (FIA) is the modern sample handling technique under heterogeneous and non-equilibrium state. It has been widely accepted in the field of automatic analysis for the advantages of high speed, versatility for on-line treatment and various detection methods, high precision, and saving of reagents. The detector is the critical part of any FIA system because to a large extent it decides both selectivity and sensitivity of a particular determination. It has been proved advantageous to combine the FIA with electrochemical detection method.FIA with electrochemical detection has played an important role in the fields of FIA methodology owing to its simplicity. Up to date, there are two kinds of electrochemical methods employed in FIA. One is based on the charge transfer between the analyte and conductive or semi-conductive solid phase, or charge transfer between the analyte and non-mixing liquid phase. This kind of method includes potentiometry, amperometry, biamperometry, coulometry and so on. The other is related to the electrochemical characteristics such as conductance and relative permittivity, mainly including conductance method. Conductance method is mostly used in online detection of ion chromatogram (IC) because of its non-selectivity. Owing to its low sensitivity, high noise signal and susceptibleness to temperature, conductance method is limitedly employed in FIA.Biamperometry is an electrochemical method that is based on the principle of end-point detection and with two identical polarized platinum electrodes. Under a small applied potential difference (usually 10-200 mV), the change of current between two electrodes is the object of detection. This method is very suitable to the reversible or pseudo-reversible system when both the oxidized and the reduced formsof the same species coexisted in the solution, when the concentration of the one reactant is high enough, the linearity between the cell current and the concentration of the other reactant of interest could be obtained over certain range. The reversible biamperometry suffers from down selectivity thanks to the characteristic of the homogeneous reaction and only few reversible couples such as I2/I-, Fe3+/Fe2+ have been used, which confine the application scope of biamperometry.In this present paper, by associating the two irreversible and independent couples to form the pseudo-reversible biamperometry, flow injection systems are established for several important compounds related to pharmaceutics, environment and industry. Furthermore, the above-mentioned method showed high sensitivity, high selectivity and the ratio of signal to noise with the applied potential difference of 0 V.This dissertation includes the works in the following aspects:Part one:The achievements on the application of electrochemical detection in flow injection analysis-are reviewed particularly with 112 references.Part two:A flow-injection biamperometric method for direct determination of calcium dobesilate had been proposed based on biamperometric detection for irreversible couples. The detection was realized by coupling the oxidation of dobesilate at one platinum wire electrode with the reduction of MnCV at another one with the applied potential difference of 0 V between the two electrodes. Calcium dobesilate was determined in the range of 4.0 X 10-6~1.0X 10-4 mol l-1 with the detection limit of 8.0 X 10-7 mol l-1 (S/N = 3). The relative standard derivation of 1.7 % was obtained for 24 successive determinations of 4.0 X10-5 mol l-1 dobesilate. Most excipients, ions and biochemical substances added did not interfere with the determination.Part three:The method is based on electrocatalytic oxidation of ethamsylate at one platinum electrode and the reduction of permanganate at another one to form an irreversible biamperometric detection system. Ethamsylate can be determined over the range1.0x10-6-1.0x10-4mol l-1 with a sample measurement frequency of 180 samples h-1. The detection limit for ethamsylate is 4.0x10-7 mol l-1 and the stabi...
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