title: Rapid measurement of deuterium-labeled long-chain fatty acids in plasma by HPLC-ESI-MS.
abstract: Imbalanced fatty acid metabolism contributes significantly to the increased incidence of metabolic disorders. Isotope-labeled fatty acids (2H, 13C) provide efficient means to trace fatty acid metabolism in vivo. This study reports a new and rapid method for the quantification of deuterium-labeled fatty acids in plasma by HPLC-MS. The sample preparation protocol developed required only hydrolysis, neutralization, and quenching steps followed by high-performance liquid chromatography-electrospray ionization-mass spectrometry analysis in negative ion mode using single ion monitoring. Deuterium-labeled stearic acid (d7-C18:0) was synthesized to reduce matrix interference observed with d5 analog, which improved the limit of detection (LOD) significantly, depending on the products analyzed. Linearity > 0.999 between the LOD (100 nM) and 30 microM, accuracy > 90%, precision > 88%, and adequate recovery in the dynamic range were obtained for d7-C18:0 and d7-oleic acid (C18:1). Upon oral dosing of d7-C18:0 in rats, the parent compound and its desaturation and beta-oxidation products, d7-C18:1 and d7-C16:0, were circulating with a maximal concentration ranging from 0.6 to 2.2 microM, with significant levels of d7-fatty acids detected for up to 72 h.
authors.affiliation: Merck Frosst Canada & Co., Medicinal Chemistry Department, Kirkland, Quebec, Canada H9H 3L1. sebastien_gagne@merck.com
authors.forename: Sébastien
authors.initials: S
authors.lastname: Gagné
authors.forename: Sheldon
authors.initials: S
authors.lastname: Crane
authors.forename: Zheng
authors.initials: Z
authors.lastname: Huang
authors.forename: Chun Sing
authors.initials: CS
authors.lastname: Li
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Bateman
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Lévesque
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003903:Deuterium; D005230:Fatty Acids, Nonesterified / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification*; D006801:Humans; D007553:Isotope Labeling / Q000379:methods; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods
chemical_list: D005230:Fatty Acids, Nonesterified; D003903:Deuterium