title: Characterization of acyl chain position in unsaturated phosphatidylcholines using differential mobility-mass spectrometry.
abstract: Glycerophospholipids (GPs) that differ in the relative position of the two fatty acyl chains on the glycerol backbone (i.e., sn-positional isomers) can have distinct physicochemical properties. The unambiguous assignment of acyl chain position to an individual GP represents a significant analytical challenge. Here we describe a workflow where phosphatidylcholines (PCs) are subjected to ESI for characterization by a combination of differential mobility spectrometry and MS (DMS-MS). When infused as a mixture, ions formed from silver adduction of each phospholipid isomer {e.g., [PC (16:0/18:1) + Ag](+) and [PC (18:1/16:0) + Ag](+)} are transmitted through the DMS device at discrete compensation voltages. Varying their relative amounts allows facile and unambiguous assignment of the sn-positions of the fatty acyl chains for each isomer. Integration of the well-resolved ion populations provides a rapid method (< 3 min) for relative quantification of these lipid isomers. The DMS-MS results show excellent agreement with established, but time-consuming, enzymatic approaches and also provide superior accuracy to methods that rely on MS alone. The advantages of this DMS-MS method in identification and quantification of GP isomer populations is demonstrated by direct analysis of complex biological extracts without any prior fractionation.
authors.affiliation: School of Chemistry University of Wollongong, New South Wales 2522, Australia.
authors.forename: Alan T
authors.initials: AT
authors.lastname: Maccarone
authors.affiliation: School of Chemistry University of Wollongong, New South Wales 2522, Australia.
authors.forename: Jackson
authors.initials: J
authors.lastname: Duldig
authors.affiliation: School of Medicine, University of Wollongong, New South Wales 2522, Australia.
authors.forename: Todd W
authors.initials: TW
authors.lastname: Mitchell
authors.affiliation: Central Analytical Research Facility, Queensland University of Technology, Queensland 4000, Australia.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Blanksby
authors.affiliation: AB SCIEX, Concord, Ontario L4K 4V8, Canada.
authors.forename: Eva
authors.initials: E
authors.lastname: Duchoslav
authors.affiliation: AB SCIEX, Concord, Ontario L4K 4V8, Canada.
authors.forename: J Larry
authors.initials: JL
authors.lastname: Campbell
mesh_terms: D013058:Mass Spectrometry / Q000379:methods*; D010713:Phosphatidylcholines / Q000032:analysis*
chemical_list: D010713:Phosphatidylcholines
keywords: differential mobility spectrometry; lipid isomers; mass spectrometry; sn-positional isomers