Analysis of small molecules in biological samples using capillary electrophoresis

The applications of capillary electrophoresis coupled with various detection methods, such as mass spectrometry, laser-induced fluorescence and thermal lens absorbance are demonstrated to study small biological molecules.; On-line electrospray mass spectroscopy is successfully coupled with capillary electrophoresis to rapidly and sensitively determine eight amines normally present in food. Combining both the advantages of CE and MS, this method is used to determine amines which are undetectable with UV or LIF detection system. For the other amines, the dynamic range and the detection limits are comparable to those obtained using conventional UV absorbance.; Fluorescence detection based on a sheath flow cuvette design is successfully applied to the simultaneously determine of 16 neurotransmitters in a single capillary system. Separation methodologies based on micelle electrokinetic chromatography have been developed for the analysis of neurotransmitters in brain microdialysates and homogenate samples with minimum sample pretreatment and sample requirement. The proven feasibility and reliability shows the potential to use the developed CE-LIF method to interpret the mechanism of neurotransmission and pharmacology of the drug therapy.; The design, construction, and performance of a multi-capillary detector based on thermal optical absorbance is demonstrated. This first generation multi-capillary system using a thermal absorbance detector has been developed with a typical theoretical plate number of 104. This is the first report of applying a thermal optical detection technique for use with a multiple capillary electrophoresis system.