The goal of this research is to develop the techniques of microcolumn liquid chromatography and apply them to problems in ultramicro analysis of biological systems. Microcolumn LC has the capability to handle nanoliter to picoliter sample volumes and offers femtomole to sub-attomole detection limits. Research is focused on three topics: 1. Microscale analysis: Research will be aimed at development of techniques for chemical analysis of single cells. Studies will include techniques for sample manipulation and microscale chemistry at the nanoliter scale. Development of an Edman degradation protein sequencing scheme at the femtomole level will be a highlight of this work. Another project will concern the simultaneous analysis of the size and chemical contents of single neurosecretory vesicles. 2. Detection technology: Sensitive detectors based on electrochemistry and fluorescence have been developed. The current need is for additional detection schemes which are sensitive but less selective. Microelectrospray techniques, which permit introduction of non-volatile analytes directly into gas or vacuum phase, have been developed. These techniques work at the sub-nanoliter per second flow rates characteristic of microcolumn LC. Microelectrospray coupled with mass spectrometry and photoionization detection will be studied. The goal will be to provide high quality information, such as can be obtained from mass spectra, at the attomole level. 3. Two-dimensional LC: For highly complex samples, two dimensional systems (LC/LC) offer greater resolving power than traditional one dimensional chromatography. Two-dimensional systems using microcolumn LC in both dimensions will be developed. With these systems, the high resolving power of two-dimensional separations can be applied to difficult problems involving detecting trace components in complex interfering matrices, such as the measurement of neuropeptides in single cells.
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