Table 1.

Parameters of the GC-MS system.

Parameter	Set Condition
Gas chromatography (GC)	Agilent 7890B (with Agilent 7693A autosampler)
Injection volume	1 µL
Inlet temperature	280 °C
Capillary column	HP-5MS (30 m × 0.25 mm i.d. with 0.25 μm film)
Injection mode	Splitless
Carrier gas	Helium, 1 mL/min
Temperature program	40 °C (1 min) → 120 °C (35 °C/min) → 160 °C (10 °C/min) → 300 °C (5 °C/min, hold for 10 min)
Mass selective detector (MS)	Agilent 5977A
Ionization mode	Electron ionization (EI)
Transfer line temperature	280 °C
Ion source temperature	230 °C
Quadrupole temperature	150 °C
Electronic energy	70 eV
Scan mode	Selective ion monitoring (SIM) (see Table 2)
Solvent delay	4 min