Ffap capillary column

The quantitative analysis of fecal SCFAs was performed as previously described with slight modifications [29 (link)]. About 50 mg of mouse feces was weighed with 1 mL of anhydrous methanol and vortex shook for 10 s. The mixture was then centrifuged at 10,000× g for 5 min. The supernatant was analyzed on the Agilent gas chromatography system and used FFAP capillary column (30 m × 0.25 mm × 0.25 μm) with high-purity nitrogen as the carrier gas at a flow rate of 2.96 mL/min, a splitting ratio of 1:10, an injection volume of 1 μL, and a temperature of 250 °C for both the injector and the flame ionization detector (FID). The column ramp-up procedure was as follows: the initial temperature was 80 °C for 2 min, ramped up to 180 °C at a rate of 10 °C/min, and held at 180 °C for 5 min.

Isobutanol production was analyzed by GC (Shimadzu GC-2010) equipped with a flame ionization detector (FID) and the FFAP capillary column (60 m length, 0.32-mm diameter, 1-μm film thickness) from Agilent Technologies (Santa Clara, CA, USA). GC oven temperature was initially held at 40°C for 3 minutes, then increased at a rate of 45°C min⁻¹ to 235°C and held for 4 minutes. Injector temperature was held at 225°C and FID detector temperature was held at 330°C. Injection volume was 0.5 μL, injected at a 15:1 split ratio. Helium was used as the carrier gas. 1-Pentanol was used as an internal standard.

First, 2 mL of 0.5 M NaOH–CH₃OH was saponified with 3 g of the samples at 60°C for 30 min and then allowed to react with 14% boron trifluoride at 60°C for 5 min. After completion of the reaction, methyl fatty acid ester was extracted using approximately 2 mL of hexane, followed by calculating the molar percentage of fatty acid composition at the sn‐2 position of MAG.
The GC conditions were as follows: chromatographic column, FFAP capillary column (30 m × 0.25 mm × 0.5 μm; Agilent, Santa Clara, CA, USA); detector, FID; carrier gas, N₂; flow rate, 1.0 mL/min; inlet pressure, 25 psi; and shunt ratio, 30:1. The initial furnace temperature was set at 140°C for 1 min and then increased to 230°C at a rate of 10°C/min and held for 8 min. The detector temperature was maintained at 280°C. Peak time and relative peak area were used for the quantitative and qualitative analyses of fatty acid methyl esters, respectively.