Analyses were performed on a Varian

Analyses were performed on a Varian Saturn 3800 GC/2000 ITMS system and an Agilent 6890 gas chromatograph coupled to a 5973 MSD quadrupole mass spectrometer (Agilent Technologies, Mississauga, ON, Canada). Both instruments were equipped with a HP-5MS column (30 m, 0.25 mm i.d., 0.25 μm film thickness) (Hewlett–Packard, Avondale, PA). Helium was used as the carrier gas, and set to 1.0 mL/min. The 1079 injector was set at a temperature of 270 °C (unless otherwise specified). The column temperature program was initially set at 40 °C for 2 min, ramped at 10 °C/min to 180 °C, and then ramped at 20 °C/min to 300 °C and held for 5 min, for a total run time of 27 min. The ion trap was operated in full scan mode (MS). The MS operational conditions were as follows: electron ionization (EI) was maintained at 70 eV. Ion trap mass spectrometer temperatures were set at 180, 50, and 260 °C for the trap, manifold, and transfer line, respectively. For the single quadrupole mass spectrometer, the transfer line, MS Quad, and MS source temperatures were set at 280 °C, 150 °C, and 230 °C, respectively. The multiplier voltage (1 × 105 gain) was 1600 V with a multiplier offset of +200 V. Automated analysis was performed using a CTC CombiPal autosampler (Zwingen, Switzerland) and the associated Cycle Composer software (version 1.4.0). The PAL was equipped with an SPME fiber holder, a temperature controlled six-vial agitator tray, and a fiber conditioning device.