GC–MS analyses were conducted on a GCMS-QP2010 Plus spectrometer (Shimadzu, Japan) equipped with RTX-5MS
capillary column (5% biphenyl 95% dimethyl polysiloxane, 30 m×0.25 mm×0.25 m). Helium was adopted as the carrier
gas. The flow rate of helium was 1.2 mL/min. The specific column temperature program of GC used in this study was as follows: 313 K (hold 3 min)→463 K (12 K/min, hold 1 min)→563 K (8 K/min, hold 20 min). The temperature in the injection chamber was 543 K,and the temperature of transfer line was 553 K. In addition, the temperature of ion source was 503 K and the mass range was 40–450 m/z.