(2007) with some modifications: the reaction mixture was dissolved in n-hexane to a total volume of 200 mL and 150 mL of 0.8 N KOH (hydro-alcoholic solution with 30% ethanol) added. This mixture was agitated and the hydro-alcoholic phase (containing the FFAs as their potassium salts), and the hexane phase (containing the novel TAGs), decanted. The hydro-alcoholic phase was extracted twice more with 20 mL of n-hexane and both n-hexane solutions mixed together. FG-4592 datasheet The hexane was evaporated off and the extracted SLs weighed. It was possible to extract
75–80% of the SLs with a purity of over 90% using this procedure. The acylglycerols (monoacylglycerol, MAG; diacylglycerol, DAG; and triacylglycerol, TAG) and the FFAs were identified by thin-layer chromatography (TLC), and the FA compositions of the original soybean oil and of the purified SLs determined by gas chromatography (GC). Identification of the acylglycerols by TLC was carried out on silica-gel plates (pre-coated TLC plates, SIL G-25; Aldrich Chemical Co., Milwaukee, WI, USA) activated by heating at 105 °C for 20 min. The
samples and authentic standards were spotted directly onto the plate (0.1 mL) and developed in a chloroform/acetone/methanol (95:4.5:0.5, v/v/v) mobile phase. The spots of each lipid were visualised by spraying the plate with iodine vapour in a nitrogen stream. The FAs of the original soybean oil and of the purified SLs were converted into FAME by treatment with methanol-BF3 as described in the AOCS (1998) (AOCS Official Method Ce 1f-96), and analysed by gas chromatography using a Chrompack click here GC equipped with a flame ionisation detector. The separations were carried
out using a 50-m fused silica capillary column (WCOT CP-Sil 88, Chrompack, Chromtech, MN, USA) with a temperature programme from 180 to 220 °C at 5 °C/min. Hydrogen was used as the carrier gas. The injector temperature was set at 250 °C and the detector temperature at 280 °C. The FA composition was identified by comparing the retention times with authentic standards (Sigma Chemical Co.) and determining the relative percentages. EASI-MS is an ambient ionisation technique allowing for the direct and fast these MS analysis of samples in an open atmosphere directly from solid surfaces, with little or no sample preparation (Alberici et al., 2010). EASI(+)-MS performed on a tiny single droplet of an oil sample placed on an inert surface under ambient conditions, has recently been shown to provide characteristic TAG profiles for different types of vegetable oil, with proper qualitative responses (Simas et al., 2010). Spectra from the original soybean oil and the purified SLs were obtained in the positive ion mode, using a single-quadrupole mass spectrometer (Shimadzu LCMS 2010, Shimadzu Corp., Kyoto, Japan) equipped with a homemade EASI source, which is described in detail elsewhere (Haddad, Sparrapan, Kotiaho, & Eberlin, 2008).