2.2.2. GC-MS/MS

A GC-MS/MS system with an Agilent 7890A+ gas chromatograph (Palo Alto, CA, USA), 7693B autosampler, split/splitless injector, and 7000B tandem mass spectrometry detector with an electron ionization source was used for the analysis. Chromatographic separation was carried out on an HP-5 MS UI capillary column (30 m × 0.25 mm ID, 0.25 μm, Agilent Technologies, Palo Alto, CA, USA) using helium with 99.9999% purity as the carrier gas (constant flow 0.9 mL/min). The injection volume was 1 μL. The following furnace temperature program was used: initial temperature 80 ◦C held for 1 min, increased by 40 ◦C/min to 200 ◦C, 2.3 ◦C/min to 210 ◦C (held for 5 min), and increased by 10 ◦C/min

to 320 ◦C. The analysis time was 38 min. The remaining conditions were as follows: inlet temperature was 280 ◦C, transfer line temperature was 295 ◦C, source temperature was 300 ◦C, MS1 and MS2 quadrupole temperatures were 150 ◦C, collision gas flow rate (N2) was 1.5 mL/min, and quenching gas flow rate (He) was 2.25 mL/min. Mass Hunter B.07.01 software was used to control the GC-MS/MS system and to archive the data.
