Enantiomeric separations and microorganism studies with analytical separation techniques
This dissertation is divided into two parts: Part I involves enantiomeric separations by high performance liquid chromatography (HPLC) and capillary electrophoresis (CE); Part II describes a series of microorganism studies using CE.
In Part I, Chapter 1 gives an overview of enantiomeric separations using HPLC and CE. Chapter 2 presents enantiomeric separations on a new synthetic LC chiral stationary phase (CSP), i.e., a pentaproline-based CSP. The enantiomeric separation ability of this new CSP was evaluated by injecting 194 racemates on the LC column. The chiral recognition mechanism was discussed and sample loading was briefly tested. Chapter 3 shows the enantiomeric separations of three groups of synthetic chiral compounds using CE: furan derivatives, fused polycycles and isochromene derivatives. Cyclodextrin-modified micellar capillary electrophoresis (CD-MCE) was utilized in this study. The reason for using this complicated method rather than the simplest capillary zone electrophoresis (CZE) was discussed and different types of cyclodextrin selectors were compared.
In Part II, Chapter 4 serves as an introduction to this part of the dissertation: a review of work mainly from our group on microorganism studies using CE, focusing on the detection of microbial contamination and further evaluating the possibility of using CE to replace the traditional sterility test outlined in the U.S.Pharmacopeia. Chapter 5 presents a successful single-cell detection approach using a modification of a previously established procedure from our group, and thereby greatly widens the practicality and effectiveness of the method. Chapter 6 is a CE study on the use of ionic liquids (ILs) in the detection of microbial contamination. By using dicationic ILs as auxiliary buffer additives, we are able to further reduce the possibility of lysing cells by surfactants (such as CTAB).