Tq8040 mass spectrometer

For peak separation and detection, a GC 2010 gas chromatograph equipped with a HP-5 fused silica capillary column (30 m × 0.25 mm × i.d. × 0.25 μm) connected to a triple quadrupole mass spectrometer (SHIMADZU GC-2010 Plus GC system and SHIMADZU TQ8040 mass spectrometer) was used. The chromatographic conditions were as follows: the injection port was heated at 250 °C. Helium was used as a carrier gas, and the flow rate was 1 mL/min. The GC temperature program was set at 50 °C for 2 min, after which it was programed to increase from 40 to 150 °C by 4 °C/min, maintained at 150 °C for 1 min, increased from 160 to 250 °C by 5 °C/min, and finally maintained at 250 °C for 5 min. The following conditions of MS were used: (i) The ion source was electrospray ionization (ESI); (ii) the transfer line and the ion source was heated at 250 °C; (iii) the mass spectrometer was operated in the electron impact of 70e V, scanning the range of 45/500 m/z in full scan acquisition mode, with a scan rate of 0.2 scan/s. The mass spectra and retention time of each GC peak in the total ion chromatography were compared with the data system library (NIST 11 MS Library). The relative abundance of each compound was estimated by relative area (RA). A blank experiment (growth medium not inoculated with ETR-B22) was performed under the same conditions. All measurements were made with three replicates.

Pretreatment serum was prepared as previously described in Reference [36 (link)], with minor modifications. In brief, 500 μL of the serum was immediately acidified upon collection with 500 μL of hydrochloric acid (0.01 M), vortex mixed for 30 s, and stored at −20 °C until analysis of TMA and TMAO. The serum TMA and TMAO levels were measured by using headspace gas chromatography–mass spectrometry (GC–MS), as previously described in Reference [6 (link)]. A Shimadzu GC-2010 Plus gas chromatograph (Shimadzu, Kyoto, Japan) fitted with a 60 m × 0.20 mm ID fused silica capillary column coated with a 1.12 μm film of HP-VOC (Agilent Technologies, CA, USA) and a Shimadzu TQ8040 mass spectrometer were used. The detection was performed on a Shimadzu GCMS-QP2010 Plus system (Shimadzu Technologies, Kyoto, Japan) equipped with an HS-20 headspace sampler.