Boron trifluoride in methanol

Fatty acids methyl esters were isolated from serum with the use of the modified Folch and Szczuko methods [88 (link),89 (link)]. The fatty acids profile was labelled by gas chromatography. The gas chromatography (GC) was performed with the use of the Agilent Technologies 7890A GC System (SUPELCOWAX™)10 Capillary GC Column (15 mm × 0.10 mm, 0.10 μm); Supelco (Bellefonte, PA, USA). Chloroform and methanol (Merck), boron trifluoride in methanol, NaCl and 2,6-Di-tert-butyl-4-methylphenol (Sigma-Aldrich, St Louis, MO, USA), double-distilled water (Milli-Q Water System, Millipore, Billerica, MA, USA), fatty acids standards were supplied by Sigma-Aldrich (Darmstadt, Germany), Cayman Chemical (Ann Arbor, MI, USA) and Neochema (Bodenheim, Germany). The results of the fatty acids were presented as the percentage distribution.

The fatty acid internal standard, docosatrienoic acid (22:3n-3) ethyl ester, GC reference standard (GLC-462), fish oil ethyl DHA, and microalgal ethyl DHA were purchased from NuChek Prep, Inc (Elysian, MN). Uniformly labeled ¹³C DHA methyl ester was purchased from Cambridge Isotope Laboratories, Inc. For isotopic analysis, the reference materials (USGS70, USGS71, and USGS72) were obtained from Reston Stable Isotope Laboratory-United States (Reston, VA). Boron trifluoride in methanol (14%) was purchased from Sigma-Aldrich. All solvents used were American Chemical Society or HPLC grade and were purchased from either MilliporeSigma (Mississauga, ON, Canada) or Fisher Scientific (Ottawa, ON, Canada).

Fully hydrogenated soybean oil, interesterified soybean oil, and regular soybean oil were provided by Archer Daniels Midland Company (Decatur, IL, USA). Sunflower oil was purchased from a local grocery store.
Sodium hydroxide, sodium sulfate anhydrous, hydrochloric acid, methanol, hexane, isopropanol, and chloroform were purchased from Fisher Scientific (Hampton, NH, USA). Dioxane was purchased from Acros Organics (Fair Lawn, NJ, USA). Boron trifluoride in methanol (14% w/w), ferrous sulfate, barium chloride, ammonium thiocyanate, and cumene hydroperoxide; α-, ɣ-, and β- tocopherols; and 1-(2,5-dimethoxy-phenylazo)-naphthalen-2-ol (citrus red 2) and hexanal were purchased from Sigma-Aldrich (St. Louis, MO, USA). BODIPY 493/503 was purchased from Invitrogen (Waltham, MA, USA).