| In this thesis, a method for simultaneous determination of tyrosine and its related derivatives, such as tyramine, p-hydroxyphenylpyruvic acid, homogentisic acid, Tyr-Gly-Gly, Tyr-Arg and Tyr-D-Arg by capillary electrophoresis with UV detection (CZE-UV) was developed. Also, some on-line sample stacking methods for separating threeβ-agonists including cimaterol, clenbuterol and salbutamol were investigated. We also have studied on hymecromone, rutin and caffeic acid by capillary electrophoresis in herbal drug with capillary amperometric detection (CE-AD).Five parts are included in this thesis. In the first part, an overview on theory and applications of capillary electrophoresis especially in amino acid and agonists and Chinese traditional medicine is presented.The second part is focused on the studies of capillary electrophoresis behaviors of tyrosine and its derivatives. Seven analyses were well separated and detected using CZE-UV within 20 minutes with detection limit ofμM range. At last the recoveries of the 7 analyses in urine sample were studied, and the results were satisfactory.The third part is focused on the interaction between p-hydroxyphenylpyruvic acid andβ-cyclodextrin by electrochemical method. The kinetics of keto-enol tautomerization of p-hydroxyphenylpyruvic acid was also studied and it had been proved to be a first-order reaction and the hydrolysis rate constants of p-hydroxy- phenylpyruvic was obtained at temperature of 25℃.In the forth part, two on-line sample stacking methods, such as large volume stacking with reversed pressure and field-amplified injection were studied and optimized for the analysis of threeβ-agonists including cimaterol, clenbuterol and salbutamol. The field-amplified method had been successfully applied to analysis of human urine. The sensitivity was improved to be 30～40 fold compared to the normal CZE, and the detection limits (defined as S/N=3) of this method were found to be lower than 2.0 ng/mL for all of these threeβ-agonists.
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