Analysis of plant phosphatidylcholines by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
Article first published online: 23 MAY 2001
Copyright © 2001 John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry
Volume 15, Issue 12, pages 935–940, 30 June 2001
How to Cite
Zabrouskov, V., Al-Saad, K. A., Siems, W. F., Hill, H. H. and Knowles, N. R. (2001), Analysis of plant phosphatidylcholines by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Rapid Commun. Mass Spectrom., 15: 935–940. doi: 10.1002/rcm.318
- Issue published online: 23 MAY 2001
- Article first published online: 23 MAY 2001
- Manuscript Accepted: 18 APR 2001
- Manuscript Revised: 16 APR 2001
- Manuscript Received: 29 MAR 2001
The use of matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) for the quantitative determination of phospholipid (PL) molecular species has been problematic, due primarily to the formation of multiple signals (corresponding to the molecular ion and other adducts) for some classes of PL. For example, analysis of phosphatidylcholine (PC) yielded signals that corresponded to protonated and sodiated molecules in the MALDI spectrum. The resulting spectral overlap among various molecular species (e.g. [PC(16:0/18:2) + Na] and [PC(18:2/18:3)]) made it impossible to ascertain their relative amounts using this technique. Other spectral ambiguities existed among different structural isomers, such as PC(18:1/18:1) and PC(18:0/18:2). We determined that molecular species could be resolved by MALDI-TOFMS by first removing the polar head (e.g. phosphocholine) from the phospholipid to effect production of only the sodiated molecules of the corresponding diacylglycerols (DAGs). Analysis of the resulting spectrum allowed unequivocal determination of the molecular species profile of PC from potato tuber and soybean. Estimation of fatty acid composition based on the molecular species determined by MALDI-TOFMS analysis agreed with that from GC-FID analysis. Post-source decay (PSD) was used to resolve standard isomers of PC (e.g. 18:1/18:1 vs. 18:0/18:2). Our results indicated that PSD is a useful approach for resolving structural isomers of PL molecular species. Copyright © 2001 John Wiley & Sons, Ltd.