Faculty Collaboration Database

Molecular species composition of rat liver phospholipids by ESI-MS/MS: the effect of chromatography. J Lipid Res 2001 Dec;42(12):1959-68

Date

12/06/2001

Pubmed ID

11734568

Scopus ID

2-s2.0-0035661557 (requires institutional sign-in at Scopus site)   107 Citations

Abstract

Using electrospray ionization tandem mass spectrometry (ESI-MS/MS) this study shows that the loss of glycerophospholipid (GPL) after chromatography was unevenly distributed across the GPL molecular species. Both TLC and HPLC caused a preferential loss of GPL with 0 to 3 double bonds: 20% and 7.2% for choline glycerophosphates (PC) and 19.7% and 7.5% for ethanolamine glycerophosphates (PE), respectively. A consequence of these losses was that GPLs containing fatty acids with four or more double bonds had a greater contribution to the total after chromatography. ESI-MS/MS analysis also showed that PC molecular species with four or more double bonds migrated at the front of the TLC band of PCs. GPLs extracted from TLC plates occasionally contained PCs that were smaller than those in the original extract. These low molecular mass PCs were easily reduced to alcohols and formed derivatives with 2,4-dinitrophenylhydrazine, suggesting that aldehydes were generated by the oxidation of unsaturated fatty acids. Directly analyzing lipid extracts by ESI-MS/MS without preliminary chromatographic separation gives an accurate distribution of GPL molecular species in lipid mixtures. However, the ionization of the phospholipids in the electrospray jet maximized at relatively low concentrations of GPL. There was a linear response between phospholipid mass and ion intensity for concentrations around 1-2 nmol/ml for both PC and PE. The total ion intensity continued to increase with concentrations above 1-2 nmol/ml, but the response was non-linear.

Author List

DeLong CJ, Baker PR, Samuel M, Cui Z, Thomas MJ

Author

Michael J. Thomas PhD Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Artifacts
Cattle
Chromatography, High Pressure Liquid
Chromatography, Thin Layer
Liver
Oxidation-Reduction
Phospholipids
Rats
Silicon Dioxide
Spectrometry, Mass, Electrospray Ionization
Thermodynamics