Tsq quantum gc mass spectrometer

SCFAs were extracted based on the procedure reported by Trompette et al [14 (link)]. Briefly, 100 mg of cecum or feces were homogenized in 400 μl of H₂O containing hexanoic acid (methyl-d₃, Cambridge Isotope Laboratories, Tewksbury, MA) used as an internal standard. Then, 80 μl of 25% meta-phosphoric acid (Sigma-Aldrich, St. Louis, MO) was added to the homogenate and kept on ice for 30 min. Thereafter, samples were centrifuged at 17,500×g for 15 min at 4°C. The supernatants were filtrated using a Millipore Ultrafree MC PLHCC centrifugal filter and analyzed by gas chromatography-mass spectrometry (GC-MS). Then, 1 μl of the sample was injected with a split mode (1:100) into a TRACE GC ULTRA gas chromatograph equipped with a TSQ QUANTUM GC mass spectrometer (Thermo Fisher Scientific, Waltham, MA). A Nukol^™ fused silica capillary column (0.25 mm ID × 30 m, 0.25 μm film thickness, Supelco, Bellefonte, PA) was used for separation. The column temperature was programmed to 150°C for 2 min, increased to 200°C at a rate of 8°C/min and maintained for 13 min. Helium was used as the carrier gas at a flow rate of 0.7 ml/min. The data were acquired in electron impact ionization mode at 70 eV.

Hundred milligrams of fresh feces from C57BL/6 male mice were homogenized in 400 μl H₂O containing hexanoic acid (methyl-d₃) as an internal standard. Then 80 μl of 25% meta-phosphoric acid was added to the homogenate and kept on ice for 30 min. Thereafter, samples were centrifuged at 17,500 × g for 15 min at 4°C. The supernatants were filtered using a Millipore Ultrafree MC PLHCC centrifugal filter (Merck Millipore) and analyzed by gas chromatography-mass spectrometry (GC-MS). One microliter of the sample was injected with a split mode (1:100) into a TRACE GC ULTRA gas chromatograph equipped with a TSQ QUANTUM GC mass spectrometer (ThermoFisher Scientific, Waltham, MA). A Nukol™ fused silica capillary column (0.25 mm ID × 30 m, 0.25 μm film thickness; Supelco, Bellefonte, PA, USA) was used for separation. Column temperature was programmed for 150°C for 2 min, then increased to 200°C at a rate of 8°C/min and held at 200°C for 13 min. Helium was used as a carrier gas at a flow rate of 0.7 ml/min. Data were acquired by the electron impact ionization mode at 70 eV.