A new concept for isotope ratio monitoring liquid chromatography/mass spectrometry
Article first published online: 31 AUG 2004
Copyright © 2004 John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry
Volume 18, Issue 19, pages 2260–2266, 15 October 2004
How to Cite
Krummen, M., Hilkert, A. W., Juchelka, D., Duhr, A., Schlüter, H.-J. and Pesch, R. (2004), A new concept for isotope ratio monitoring liquid chromatography/mass spectrometry. Rapid Commun. Mass Spectrom., 18: 2260–2266. doi: 10.1002/rcm.1620
- Issue published online: 31 AUG 2004
- Article first published online: 31 AUG 2004
- Manuscript Revised: 3 AUG 2004
- Manuscript Accepted: 3 AUG 2004
- Manuscript Received: 8 JUN 2004
A new interface for the on-line coupling of a liquid chromatograph to a stable isotope ratio mass spectrometer has been developed and tested. The interface is usable for 13C/12C determination of organic compounds, allowing measurement of small changes in 13C abundance in individual analyte species. All of the carbon in each analyte is quantitatively converted into CO2 while the analyte is still dissolved in the aqueous liquid phase. This is accomplished by an oxidizing agent such as ammonium peroxodisulfate. The CO2 is separated from the liquid phase and transferred to the mass spectrometer. It is shown that the whole integrated process does not introduce isotope fractionation. The measured carbon isotope ratios are accurate and reproducible. The sensitivity of the complete system allows isotope ratio determination down to 400 ng of compound on-column. By-passing the high-performance liquid chromatography (HPLC) separation allows bulk isotopic analysis with substantially lower sample amounts than those required by conventional elemental analyzers. The results of the first applications to amino acids, carbohydrates, and drugs, eluted from various types of HPLC columns, are presented. The wide range of chromatographic methods enables the analysis of compounds never before amenable to isotope ratio mass spectrometry techniques and may lead to the development of many new assays. Copyright © 2004 John Wiley & Sons, Ltd.