A liquid chromatography-mass spectrometry workflow for in-depth quantitation of fatty acid double bond location isomers

Abstract

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Deep Profiling of Aminophospholipids Reveals a Dysregulated Desaturation Pattern in Breast Cancer Cell Lines

“…Moreover, the average RSD of the data shown in Figure is only 3% from three biological replicates (Table S6, Supporting Information). The same characteristics have been reported for lipid CC location isomer analysis from tissue, plasma, and single cells . The data reveal structural diversity of lipid molecular species down to the CC location level and highlight that CC location isomers are distributed heterogeneously among lipid species.…”

Deep-lipidotyping by mass spectrometry: recent technical advances and applications

“…A series of aryl ketones and aldehydes have been developed besides acetone, rendering flexibility in choosing the most suitable PB reagents for a specific application in lipid analysis ( 63 ). For instance, acetyl pyridines (3- and 2-acpy) have been developed as the charge-tagging/charge-switching PB reagents, which improve the LOI for nonpolar lipids including FAs, cholesteryl esters (CEs), and GLs down to the C=C location level ( 64 , 65 ). By coupling 2-acpy PB reaction with MS 3 or MS 4 -CID, the locations of C=Cs can be confidently determined with sn -chain specificity for GPLs ( 66 ).…”

“…When the total quantity of the isomer is known, the concentration information can be further obtained. Examples of isomer quantitation following this principle have been shown for both C=C location isomers and sn -isomers ( 58 , 65 ). When the standards are not available, only “relative fractional quantitation” can be obtained because how the structural differences of the isomers might affect ionization and fragmentation is unknown.…”

“…For instance, the relative compositions of the n-9 and n-7 isomers of C18:1 in a variety of PCs and PEs were found to change significantly between plasma samples of normal control and type 2 diabetes (T2D) patients and tissue samples from breast cancer patients using an LC-PB-MS/MS method ( 59 ). In combination with methylation and charge tagging, PB-MS/MS also enabled sensitive screening of potential plasma lipid C=C isomer biomarkers of T2D in other classes of lipids such as anionic GPLs ( 61 ), FAs ( 65 ), DAGs, and TAGs ( 117 ). By discrimination of both C=C and sn -isomers of GPLs, it showed further advantage in phenotyping different disease states and discovery of differentiating lipids ( 66 ).…”

Liquid Chromatography-Mass Spectrometry (LC-MS) Derivatization-Based Methods for the Determination of Fatty Acids in Biological Samples

“…2′,4′,6′-Trifluoroacetophenone (triFAP) ( Figure 9 ) stood out among the ketones studied, providing an increase in the P–B reaction yield for different types of C=C bonds and high sensitivity (subnanomolar range) for C=C bond identification [ 87 ]. More recently, Xia and co-workers investigated the use of various acetyl pyridines, as well as pyridine derivatives of benzophenone, as derivatization reagents enabling charge reversal, and concluded that 2-acetylpyridine (2-acpy) ( Figure 9 ) leads to LODs in the subnanomolar range for MUFAs, PUFAs, as well as conjugated FAs [ 88 ]. The same derivatization reagent was applied for the determination of position-specific quantitative deuterium abundancies in bis-allylic deuterated highly unsaturated fatty acids (D-HUFA) (a novel class of drugs stabilized against H abstraction-mediated oxidation) by a shotgun lipidomics analysis [ 89 ].…”