Table 1. GC/MS operating conditions

Column	VF-5MS capillary column
	(60 m × 0.25 mm, 0.25 μm; Agilent Technologies, Santa Clara, CA, USA)
GC oven	50°C, hold 5 min
	10°C/min to 65°C, hold 30 min
	5°C/min to 210°C, hold 10 min
	20°C/min to 325°C, hold 10 min
Carrier gas	He (1 mL/min, 25 psi)
Linear velocity	19.8 cm/s
Injection mode	Split 1:20
Injection temperature	250°C
MS parameters		FID parameters
MS ionization mode	EI	FID temperature	300°C
Scan time	0.2 s	Hydrogen flow	35.0 mL/min
Mass range	35–550 amu	Air flow	350.0 mL/min
Ion source temperature	270°C	Make up flow	40.0 mL/min
Interface temperature	250°C