Quantitative Profiling of Major Neutral Lipid Classes in Human Meibum by Direct Infusion Electrospray Ionization Mass Spectrometry
- 1 August 2013
- journal article
- research article
- Published by Association for Research in Vision and Ophthalmology (ARVO) in Investigative Ophthalmology & Visual Science
- Vol. 54 (8), 5730-5753
- https://doi.org/10.1167/iovs.12-10317
Abstract
Purpose. The purpose of this investigation was to better understand lipid composition in human meibum. Methods. Intact lipids in meibum samples were detected by direct infusion electrospray ionization mass spectrometry (ESI-MS) analysis in positive detection mode using sodium iodide (NaI) as an additive. The peak intensities of all major types of lipid species, that is, wax esters (WEs), cholesteryl esters (CEs), and diesters (DEs) were corrected for peak overlapping and isotopic distribution; an additional ionization efficiency correction was performed for WEs and CEs, which was simplified by the observation that the corresponding ionization efficiency was primarily dependent on the specific lipid class and saturation degree of the lipids while independent of the carbon chain length. A set of WE and CE standards was spiked in meibum samples for ionization efficiency determination and absolute quantitation. Results. The absolute amount (μmol/mg) for each of 51 WEs and 31 CEs in meibum samples was determined. The summed masses for 51 WEs and 31 CEs accounted for 48 ± 4% and 40 ± 2%, respectively, of the total meibum lipids. The mass percentages of saturated and unsaturated species were determined to be 75 ± 2% and 25 ± 1% for CEs and 14 ± 1% and 86 ± 1% for WEs. The profiles for two types of DEs were also obtained, which include 42 α,ω Type II DEs, and 21 ω Type I-St DEs. Conclusions. Major neutral lipid classes in meibum samples were quantitatively profiled by ESI-MS analysis with NaI additive.This publication has 72 references indexed in Scilit:
- Recommendations for Mass Spectrometry Data Quality Metrics for Open Access Data (Corollary to the Amsterdam Principles)Molecular & Cellular Proteomics, 2011
- Accurate Quantification of Lipid Species by Electrospray Ionization Mass Spectrometry — Meets a Key Challenge in LipidomicsMetabolites, 2011
- Analysis of cholesteryl esters and diacylglycerols using lithiated adducts and electrospray ionization-tandem mass spectrometryAnalytical Biochemistry, 2011
- Lipidomics of human Meibomian gland secretions: Chemistry, biophysics, and physiological role of Meibomian lipidsProgress in Lipid Research, 2011
- Multi‐dimensional mass spectrometry‐based shotgun lipidomics and novel strategies for lipidomic analysesMass Spectrometry Reviews, 2011
- New Applications of Mass Spectrometry in Lipid AnalysisJournal of Biological Chemistry, 2011
- Fatty acid composition of cholesteryl esters of human meibomian gland secretionsSteroids, 2010
- Electrospray ionization multiple-stage linear ion-trap mass spectrometry for structural elucidation of triacylglycerols: Assignment of fatty acyl groups on the glycerol backbone and location of double bondsJournal of the American Society for Mass Spectrometry, 2010
- The Meibomian Puzzle: Combining pieces togetherProgress in Retinal and Eye Research, 2009
- Ion mobility–mass spectrometryJournal of Mass Spectrometry, 2008