Development of novel enantiomeric separation techniques and applications to real-world samples.

摘要

High efficiency enantioselective separation techniques are among the most convenient and reliable methods for determining and monitoring the stereochemical composition of biologically important compounds. Novel enantiomeric separation techniques have been developed in the course of this research. Antibiotic avoparcin and dimethylated beta-cyclodextrin were developed as new chiral stationary phases (CSPs) for HPLC and pentosan polysulfate was used as a chiral additive for CE. A large number of racemic compounds were resolved using these new techniques. The enantioselectivity of the new chiral selectors was compared to that of other antibiotic, cyclodextrin or polysaccharide chiral selectors. The chiral recognition mechanism was investigated.;The application of chiral separation techniques was demonstrated on a few real-world samples. First, the enantiomeric composition of nicotine and related alkaloids in tobacco and medicinal products was determined using HPLC and GC-MS techniques with appropriate CSPs. It was found that the alkaloids exist with distinctive enantiomeric ratios in tobacco. The enantiomeric compositions of monoterpenes in conifer resins were then investigated. It was observed that the monoterpene composition is species-specific and sometimes the enantiomeric ratios change considerably with the age of the tree. Finally some hydrocarbons (i.e., chiral indans and tetralins) were investigated as light biomarkers in crude oils and coals. All the hydrocarbons under investigation were found to be racemic. The implication and significance of the stereochemical information of various molecules in biological or geological matrices were discussed.