Rtx 2330 column

Experimental oil was mixed following Liao’s method [18 (link)]. Soybean oil and experimental oil mixture were purchased from a local supermarket and analyzed by gas chromatography (GC). Samples were extracted using a modified Folch method [19 (link)]. Samples was extracted using chloroform/methanol = 2/1 (v/v) for 1 h, and then distilled water was added to separate the liquid. The extract was incubated for 10 min at room temperature and centrifuged at 4 °C and 3000 rpm for 10 min. The lower phase was collected. FA methylation was performed by heating the sample to 88 °C with 14% boron trifluoride/methanol (B1252, Sigma, St. Louis, MO, USA) for 1 h to form FA methyl ether (FAME) and then the solvent was removed. FAME was analyzed using a FOCUS™ GC (Thermo Fisher Scientific, Milan, Italy) equipped with a 30-m × 0.32-mm inner diameter (I.D.) × 0.20-μm df Rtx-2330 column (Restek, Bellefonte, PA, USA) and flame ionization detector.
FA compositions of the soybean oil and experimental oil were analyzed by GC. Results were obtained based on the retention time of the appropriate standard (GLC-455; Supelco, St. Louis, MO, USA), and percentages of the FA profile were calculated based on 16 different FAs, as shown in Table 1.

To check absorption of fatty acids by mice, the fatty acid composition of plasma lipids was assessed by gas chromatography. Plasma total lipids were extracted by the method of Bligh and Dyer with chloroform: methanol (2:1, v:v). Methyl esters of fatty acids were obtained by transesterification with boron trifluoride in methanol at 80 °C for 60 min. An aliquot containing the methyl esters of fatty acids was analyzed by gas chromatography (Hewlett-Packard model 5890) on a 30 m RTX-2330 column (Restek, Bellefonte, PA, USA) with an internal diameter of 0.25 mm equipped with a flame ionization detector. The carrier gas was helium at a pressure of 105 kPa. For the total separation of the different compounds, two temperature settings were established: 140 °C–200 °C at 3 °C/min or in two stages of 140 °C–180 °C at 4 °C/min and 180 °C–210 °C at 2 °C/min. The temperature of the injector and detector was 260 °C. The linear response of the detector was tested periodically with standard mixtures. Typically, two internal standards with different molecular weight (13:0 and 23:0 or 27:0) were used. Peaks were integrated with an integrator D-2500 (Hitachi Ltd., Tokyo, Japan) and identified by comparison of retention times with standards. When necessary, the identification may be confirmed by mass spectrometry (Hewlett-Packard detector model 5970B) at an ionization potential of 70 eV.