Docosapentaenoic acid

The following chemicals were purchased from Tokyo Chemical Industry (Tokyo, Japan): n-octanoic acid (C8:0), lauric acid (C12:0), myristic acid (C14:0), palmitic acid (C16:0), cis-9-hexadecenoic acid (C16:1), stearic acid (C18:0), γ-linolenic acid (C18:3), cis-5,8,11,14,17-eicosapentaenoic acid (EPA; C20:5) and arachidonic acid (C20:4). Decanoic acid (C10:0), 9-decenoic acid (C10:1), oleic acid (C18:1), arachidic acid (C20:0), all-cis-7,10,13,16,19-docosapentaenoic acid (DPA, C22:5), docosanoic acid (C22:0), tetracosanoic acid (C24:0), hexacosanoic acid (C26:0), DAABD-AE, N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC), 4-(dimethylamino) pyridine (DMAP) and perfluorooctanoic acid (PFOA) were purchased from Sigma-Aldrich (Taufkirchen, Germany). The following deuterium or ¹³C labeled analogs used as IS were purchased from Cambridge Isotopes Laboratories (Tewksbury, MA, USA): ¹³C₄-C8:0, d₃-C10:0, d₃-C12:0, d₃-C14:0, d₄-C16:0 and d₃-C18:0. PRA, PHA, d₃-PRA, d₃-PHA, d₄-C22:0, d₄-C24:0, and d₄-C26:0 were obtained from Dr. H. J. Ten Brink (Vrije Universiteit Medical Center, Amsterdam, The Netherlands). LC-MS/MS grade acetonitrile and water were purchased from Merck (Darmstadt, Germany). Merck also supplied us with HPLC grade hexane, toluene, and heptane.

Deuterated and control diets were obtained from Research Diets, Inc (D20100101 and D20100202, New Brunswick, NJ). 11,11-d2 linoleic acid ethyl ester (DLA-EE) was provided by Retrotrope Inc. EZ-Link™ Sulfo-NHS-LC-Biotin (21,335, biotinylating reagent) and APC streptavidin were purchased from Thermo Fisher Scientific (349,024, Waltham, MA), and BD Biosciences (Franklin Lakes, NJ), respectively. Phosphate buffered saline, 1X (PBS; 21-040-CM was purchased from Corning (Corning, NY). Leukoreduction filters (AP-4952) were purchased from Pall (Port Washington, NY).
Fatty acid methyl esters (FAME) standard mixture (FAME 25) was purchased from USP (1269119; Rockville, MD), while methyl esters of arachidonic acid (AA, 2566-89-4), docosahexaenoic acid (DHA, 2566-90-7), docosapentaenoic acid (DPA, 108698-02-8), eicosapentaenoic acid (EPA, 2734-47-6), and nonadecanoate (C19:0, 1731-94-8), as well as malondialdehyde (MDA, 100,683-54-3), were purchased from Sigma (St. Louis, MO). Malondialdehyde-D2 (MDA-D2, D-6469) was purchased from CDN Isotopes (Pointe-Claire, QC, Canada). Heptane (34,873), hexane (34,859), pentane (34,956), methanol (34,860), and hydrochloric acid in methanol (90,964) were purchased from Sigma. Liquid chromatography-mass spectrometry (LC-MS) grade water was purchased from Supelco (Bellefonte, PA, WX0001). Chloroform was purchased from J.T. Baker (67-66-3, Phillipsburg, NJ).