Plrp s polymeric reversed phase column

Lipid extracts were analyzed by liquid chromatography mass spectrometry (LC-MS) using a modification of the procedures of Dillon et al. (Dillon et al., 2008 (link)). The LC-MS system consisted of a 1200 Series Capillary LC (Agilent, Santa Clara, CA) coupled to a Q-Tof micro mass spectrometer (Waters Corp., Milford, MA) equipped with an electrospray ionization source. Separation of fatty acids was achieved by isocratic elution on a PLRP-S polymeric reversed-phase column (100 Å, 3 µm, 2.1 × 150 mm; Agilent) heated to 65°C. A mobile phase consisting of 25% acetonitrile:chloroform (1:1), 40% methanol, 25% water, 10% 10 mM ammonium acetate was run at a flow rate of 0.1 ml/min. The mass spectral analysis of the fatty acids was performed in the negative ion mode using the following instrument settings: capillary voltage, 1600; sample cone voltage, 40; cone gas flow, 40 L/hr; desolvation gas flow, 400 L/hr; source temperature, 80°C; desolvation temperature, 100°C. Data was then analyzed using Masslynx software v4.1 (Waters) by extracting the ion chromatograms of the labeled and non-labeled stearic, palmitic, oleic, and palmitoleic acid peaks and measuring peak area.