I Research And Application Of New Technology In Capillary Electrochromatography Ii. Some Of The Main Active Ingredient In The Commonly Used Chinese Herbal Medicine In Rats In Vivo Metabolism Studies

Capillary electrochromatography is a novel kind of separation and analytical techniques. Developed from the nineties, it combines the advantages of high performance liquid chromatography (HPLC) and capillary electrophoresis (CE) with high resolution, high efficiency and better selectivity. The retention mechanism of capillary electrochromatography of neutral and charged compounds and the theory of column efficiency are always the focus of CEC study. We have studied the new techniques and application of CEC under the support of Chinese Association of Instrumental Analysis.â…  Reversed-phase electrochromatographic column with internal diameter of 100 μm, was successfully prepared by combination of vacuum filling and pressure compressing. It was a simple and fast method and no special equipment was needed. The efficiency of column was up to 100,000 per meter. The reproducibility of efficiency and retention time was evaluated. The mixture of thiourea and three aromatic compounds was used. RSD values of retention time were smaller than 2.2% and RSD values of efficiency were smaller than7.5%. Results showed that the homemade packed column could be used in our future investigation.â…¡ Electroosmotic flow(EOF) is the driving force of CEC, the influence of voltage, buffer concentration, acetonitrile volume fraction and column temperature on the EOF was investigated in phosphate buffer and tris-HCl buffer systems. It was found that with the increase of voltage, the EOF was improved linearly. EOF had the linear relationship with voltage within a certain voltage range. The lower the concentration of buffer was, the wider range of voltage could be used. Acetonitrile volume fraction had significant effect on EOF. With the increase of acetonitrile volume fraction the elution ability was improved. Voltage , buffer concentration and column temperature had smaller effects on EOF than acetonitrile volume fraction. All factors had approximately the same effect on EOF in C₁₈ And C₈ homemade packed columns.â…¢ Although CEC has been used to separate and analyze neutral compounds, the retention mechanism was not completely elucidated. We studied the retention behavior of neutral compounds on C₈ and C₁₈ CEC columns in phosphate buffer system and Tris buffer system. Capacity factor was the parameter for evaluation of the retention behavior.The mixture of four aromatic compounds was used. It was found...