Agilent 7890b gas chromatograph system

The dried extracts were derivatized with 5 μL of 40 mg/mL methoxyamine hydrochloride (Sigma-Aldrich, St. Louis, MO, USA) in pyridine (Thermo Fisher Scientific, USA) and incubated for methoxyamination (90 min at 200 rpm and 30°C). For the retention time index, 2 μL of a mixture of fatty acid methyl esters [FAMEs] was added and 45 μL of N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA + 1% TMCS; Thermo, USA) was combined for trimethylsilylation (1h at 200 rpm and 37°C). The FAME mixture was composed of C8, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28, and C30.
GC-MS analysis was performed as described previously [22 (link)]. Using an Agilent 7890B gas chromatograph system (Agilent Technologies) equipped with an RTX-5Sil MS column (Restek, Gellefonte, PA, USA), the derivatives (0.5 μL) were injected in splitless mode. The entire system was controlled using the ChromaTOF software 4.50 version (LECO, St. Joseph, MI, USA). Mass spectra were acquired in the 85–500 m/z at an acquisition rate of 20 spectra/s using a Leco Pegasus HT time-of-flight mass spectrometer.

The Puren hospital maintains 13 ORs with an average area of 25 square meters each. The ORs do not have scavenging systems, but instead maintain vertical laminar flow conditions. All the medical residents from the exposed group worked in the 13 ORs in the hospital. All the WAGs were collected from the breathing zone of medical residents during the conduct of surgical inhalation anesthesia in all the ORs. The gas collection lasted an hour. The measurements were performed by using a GilAir-5 sampler (Sensidyne, USA) and Agilent 7890BGas Chromatograph System (Agilent Technologies, USA) according to the instruction of the manufacturer. The average of the gas concentration of sevoflurane was calculated and shown in ppm. Measurement requirement was in accordance with procedures approved by the National Institute for Occupational Safety and Health (NIOSH) [13 ].