Part I: Sensitivity improvement on detection of Coptidis alkaloids by field-amplified sample stacking in capillary electrophoresisPart II: Sensitivity improvement on detection of Coptidis alkaloids by sweeping in capillary electrophoresis
| Autor: | Hua-Ming Tseng, 曾華明 |
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| Rok vydání: | 2004 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 92 Part I:Sensitivity improvement on detection of Coptidis alkaloids by field-amplified sample stacking in capillary electrophoresis A head-column field-amplified sample stacking (FASS) for the on-line improvement of detection sensitivity of the main alkaloids of Coptidis Rhizoma has been developed in the work. Optimum separation conditions were found as follows: background solution comprising 400 mM Tris, pH 8.6, with the addition of 15% (v/v) MeOH, voltage 25 kV, hydrodynamic injection with 150 mbar and 24 s, electrokinetic injection with 8 kV and 12 s. Both injection modes attained baseline-separation within 15 min under optimum separation conditions. The detectabilities (limits of detection) of the alkaloids were lowered to about 260-fold for electrokinetic injection and 17-fold for hydrodynamic injection with respect to the conventional sample injection. The detectability for the electrokinetic injection was even in the parts per billion (ppb) levels. Part II:Sensitivity improvement on detection of Coptidis alkaloids by sweeping in capillary electrophoresis Examples of on-line approach to sample concentration include field-amplified sample stacking (FASS) and sweeping. After an FASS method for the on-line improvement of detection sensitivity of the Coptidis alkaloids had been developed in the previous study, we further attempted the sweeping technique to improve the detectability of the same alkaloids. A simple and rapid sweeping method for the on-line improvement of detection sensitivity of the main alkaloids of Coptidis Rhizoma has been developed in the work. Optimum separation conditions were found as follows: background solution comprising 100 mM phosphoric acid, 15 mM SDS and 10% (v/v) THF with pH 1.82, voltage –25 kV, sample matrix composed of 50 mM phosphoric acid and sample injection at 1000 mbar for 60 sec. The three main protoberberine alkaloids of Coptidis Rhizoma were baseline-separated within 15 min. The detectabilities of the alkaloids were found to be 2.5 ng/ml (ppb), which was about five hundred times lower compared to the conventional sample injection method. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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