| As an important approach, high performance liquid chromatography (HPLC) -electrochemical detection (ED) has been used in the fields of chemistry, medicine, biology, environment and other sciences because of its effective separation, small injection volume and high sensitivity. In the 21st century, the development of life science is the most active. How to realize the in vivo and on-line determination of biological micro-samples has important roles to the development of biology, medicine and even to the life science. Meanwhile, to understand the working mechanism of nerve center is always the great task in life science, and the arcanum of nervous system is expected to be discovered and applied in medicine, pharmacy and other new technology areas. Besides, due to the complicated functions and components of brain tissues, the analysis of biological samples is more critical. HPLC accommodates itself to this situation properly. However, the conventional HPLC-ED has its disadvantages, such as selectivity and sensitivity, etc. So, the development of high-quality HPLC-ED plays an important role not only in analytical chemistry progress but also in the advances of biology, medicine and even in the life science.In this dissertation, we laid our emphasis on the research of novel electrochemical detectors (ECD), and established some new methods of sample, separation and analysis in life science by HPLC-ED coupled with microdialysis sampling technique. Some kinds of chemically modified electrodes (CME) which could enhance the sensitivity and selectivity in vivo analysis were developed and used as HPLC-ECD. Nano material was firstly applied in the HPLC-ED to determine the monoamine neurotransmitters and neurotoxins in cerebrospinal fluid of Parkinson's disease patients. Hence, the combination of HPLC-ED with microdialysis sampling technique provided a proper way to study chemistry impact in the complicated functions of brain. The new technology had remarkable significances on the research of brain physiology and neuroscience. The dissertation includes five chaptersPart 1. New microdialysis-electrochemical device for simultaneous determination of ascorbic acid and 5-hydroxyindole-3-acetic acid in rat striatumA new device combining microdialysis with electrochemical detector was fabricated. The microelectrode modified with poly (sulphosalicylic acid) was used in the device to simultaneously determine ascorbic acid (AA) and 5-hydroxyindole-3-acetic acid (5-HIAA) in rat striatum. The chemically modified electrode (CME) exhibited a good electrocatalytic effect on the oxidation of AA and 5-HIAA. The reason why A A and 5-HIAA have the different concentrations when they were determined by direct electrochemical detection and in conventional microdialysates was also investigated. In addition, the effect of the nitric oxide donsor, sodium nitroprusside (SNP) on 5-HIAA in rat striatum was studied. The research had important significances on controlling and monitoring the influence of medicine to neurotransmitters in medicine research.Part 2. In vivo determination of monoamine neurotransmitters in rat brain microdialysate by liquid chromatography with a thioctic/palladium-iridium oxide modified electrodeThe fabrication and application of a novel electrochemical detector (BCD) with the thioctic/ palladium-iridium oxide modified electrode for liquid chromatography (LC) were described. The chemically modified electrode (CME) had a good catalytic effect on monoamine neurotransmitters and their metabolites. It was also found that the CME could be permselective to DA cations and exile the A A anions in rat brain. In LC with ED, NE, E, DA, DOPAC, 5-HT in rat brain were separated and determined effectively at the CME. Because the monoamine neurotransmitters are important substantial basis for physiologic activity and central nervous system, it is important to determine the monoamine neurotransmitters in vivo for cerebral physiology and neuroscience.Part 3. Simultaneous determination of monoamine neurotransmitters and g...
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