9216935 Abramson This program will assemble for the first time an HPLC and a continuous flow isotope ratio mass spectrometer. The component pieces are: 1. a high performance liquid chromatograph (HPLC); 2. a Vestec Universal HPLC/MS interface; 3. a chemical reaction interface (CRI); and 4. an isotope ratio mass spectrometer system (IRMS). This proposal emerges from: the PI's development of the CRI; an extensive range of CRI-MS applications using capillary gas chromatography coupled to conventional mass spectrometers; and the recent development of an interface to the CRI for HPLC that makes this approach possible. The unique chemistry of the CRI should improve l5N determinations compared with classical combustion methods. This type of instrument offers researchers who use isotopes and IRMS an expanded range of target molecules including intact biological polymers. Compared to HPLC/conventional MS approaches, 13C and l5N will be selectively detected at greatly reduced isotopic abundance. In addition, intact biological macromolecules can be analyzed directly by the CRI-IRMS for isotopic quantitation. This will greatly improve analyses in biological systems where either 14C would have been a tracer or where the tedious sequence of hydrolysis followed by chromatographic separation and MS analysis of selected monomers would be required.
