Study On Electrochemical And Capillary Electrophoresis Behavior Of Tyrosine And Its Metabolites/Derivatives And Some Alkaloids

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 amperometric detection(CZE-AD) was developed. We have also studied on berberine, palmatine and jatrorrhizine in traditional Chinese herbal drug by MECC-AD and about their electrochemical properties.Six parts were involved in this thesis. The first part is a review of the applied of CE in amino acid and traditional Chinese herbal drug.Since capillary electrophoresis with amperometric detection has great superiority on separation and determination of electrochemical active substances, in the second part, capillary electrophoresis with amperometric detection was applied to separate and determine tyrosine and its related derivatives. They were well separated within 20 minutes with detection limit of nM range. And the method has been successfully applied to analyze the metabolic process of Tyr in rabbit urine. The third part is focused on the studies of capillary electrophoresis behaviors of the keto-enol tautomerization of p- hydroxyphenylpyruvic acid.In Chapter four and five, the electrochemical behavior of palmatine and jatrorrhizine on a carbon nanotube modified electrode was investigated respectively. A highly selective and sensitive method for detection of these two compounds by osteryoung square wave stripping voltammetry was developed with detection limit of 0.05 mg/mL and 0.012 mg/mL respectively. Cyclic voltammetry, linear sweep voltammetry and chronocoulometry were employed to investigate the mechanism of the electrochemical reaction.In Chapter six, based on the investigation of the electrochemical characteristics of berberine, palmatine and jatrorrhizine, a method for simultaneous separation and detection of these three compounds by capillary electrophoresis with amperometric detection was developed. Under the optimum conditions, the analytes were separatedcompletely within 15 min, the method was employed to investigated the content of these three alkaloids in Phellodendri Cortex and Coptidis Rhizoma, and good results were obtained.