title: Desorption/ionization efficiencies of triacylglycerols and phospholipids via EASI-MS.
abstract: Knowledge of the major effects governing desorption/ionization efficiency is required for the development and application of ambient mass spectrometry. Although all triacylglycerols (TAG) have the same favorable protonation and cationization sites, their desorption/ionization efficiencies can vary dramatically during easy ambient sonic-spray ionization because of structural differences in the carbon chain. To quantify this somewhat surprising and drastic effect, we have performed a systematic investigation of desorption/ionization efficiencies as a function of unsaturation and length for TAG as well as for diacylglycerols, monoacylglycerols and several phospholipids (PL). Affinities for Na(+) as a function of unsaturation level have also been assayed via comprehensive metadynamics calculations to understand the influence of this phenomenon on the ionization efficiency. The results suggest that dipole-dipole interactions within a carbon chain tuned by unsaturation sites govern ionization efficiency of TAG and PL.
authors.affiliation: ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas - UNICAMP, Campinas, 13083-970, SP, Brazil.
authors.forename: Anna Maria A P
authors.initials: AM
authors.lastname: Fernandes
authors.forename: Gabriel D
authors.initials: GD
authors.lastname: Fernandes
authors.forename: Daniel
authors.initials: D
authors.lastname: Barrera-Arellano
authors.forename: Gilberto F
authors.initials: GF
authors.lastname: de Sá
authors.forename: Roberto D
authors.initials: RD
authors.lastname: Lins
authors.forename: Marcos N
authors.initials: MN
authors.lastname: Eberlin
authors.forename: Rosana M
authors.initials: RM
authors.lastname: Alberici
mesh_terms: D056004:Molecular Dynamics Simulation; D010743:Phospholipids / Q000032:analysis / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014280:Triglycerides / Q000032:analysis / Q000737:chemistry*
chemical_list: D010743:Phospholipids; D014280:Triglycerides
keywords: desorption/ionization efficiency; easy ambient sonic-spray ionization; lipids; molecular dynamics simulation; phospholipids; triacylglycerols