Gc solution program

The SCFA levels in mouse faecal samples were measured according to a previously reported method [19 ]. An appropriate amount of the sample was added to 0.3 mL of water, 100 μL of 50% sulfuric acid, 25 μL of 500 mg/L internal standard (cyclohexanone) solution and 0.5 mL of ether, after which the mixed solution were homogenated for 1 min and centrifuged at 12,000 rpm at 4 °C for 10 min. The supernatant was placed on the instrument for testing (Gas Chromatograph-Mass Spectrometer, Shimadzu GCMS QP2010-Ultra, Japan). The chromatographic system was as follows: Agilent DB-WAX capillary column (30 m × 0.25 mm × 0.25 μm). The carrier gas was high purity helium (≥ 99.9%), and the flow rate was 1.0 mL/min. The inlet temperature was 220 °C, the injection volume was 1 μL, and the solvent delay time was 2.5 min for splitless injection. For the mass spectrometry system, an electron bombardment ion source (EI) was used, the ion source temperature was 230 °C, and the interface temperature was 220 °C. The chromatograph was connected to a microcomputer with a detector for collecting the results of the chromatographic analysis with the GC Solution program (Shimadzu, Japan).