| Post-column electrochemical derivatization (ED) technique is usually used in the reversed phase high performance liquid chromatographic system (RP-HPLC). However, liquid chromatography is not compatible with electrochemical derivatization technique due to the narrow pH range and high proporation of organic solvent used in the mobile phase. The mobile phase of ion chromatography (IC), which is mainly composed of ionized buffer solution, can be used with full pH range since the organic polymer-based ion exchanger is usually employed as stationary phase. This feature lets IC have good compatibility with post-column electrochemical derivatization. The present thesis reported the fabrication of two kinds of electrochemical equipments for derivatization, as well as the method of ion chromatography combined with online post-column electrochemical derivatization and optical detection for the determination of ionized organic species and metal ion, which enlarged the application scope of IC.There are six parts in the thesis:in the first part, the application of post-column electrochemical derivatization technique used in the liquid chromatographic system was introduced. The poor compatibility between the liquid chromatography and electrochemical derivatization was also pointed out, along with the introduction of slight difference between the RP-HPLC and IC in the fields of separation and application. Finally, the feasibility of ion chromatography combined with electrochemical derivatization was proposed.In the second part, an electrolytic cell (EC) composed of plannar plated electrode and ion exchange membrane was fabricated. Performances of the cell, such as structure, electro-oxidation mechanism, and electro-oxidation efficiency, were discussed. Using this electrolytic cell, the method of ion chromatography combined with post-column derivatization and fluorescence detection (IC-ED-FD) was developed for the determination of folic acid (FA) and methotraxate (MTX) in the plasma of patients being treated with rheumatoid arthritis (RA) and diffuse large B cell lymphoma.In the third part, The chromatographic behavior of ionized organic substance (cabarmazepine, CBZ) was studied using IC-UV as well as IC-ED-FD. The determination of CBZ in the plasma of patients of epilepsy was also developed. Good sensitivity and selectivity were obtained due to the combination of electrochemical derivatization and fluorescence detection.In the fourth part, an electrolytic cell consisting of porous electrode and cation exchange membrane was fabricated. Phenolic compounds were electro-oxidized in this EC after ion chromatographic separation and was then detected fluorometrically. Good separation of phenols was obtained using basic eluent, and the strong electro-oxidation capability of EC could be obtained using porous electrode with large effective surface area. The analysis procedure as well as operation cost was simplified using the basic eluent. Moreover, the sensitivity was improved to a great extent using the porous electrode and time-programmed potential over the EC.In the fifth part, tyrosine in the baverage was determined using the method described in the fourth part.Finally, the method of ion chromatography combined with post-column electrochemical derivatization and ultiviolate detection was developed for the determination of magnism (II) in environmental water. The effect between the structure of the EC and electrochemical derivatization performance was prelimilarily discussed. |
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