6890n gc 5975c vl msd system

The GC-MS system was an Agilent 6890N GC/5975C VL MSD system equipped with an Agilent 7683 Automatic Liquid Sampler (Agilent technologies, Inc., Santa Clara, CA, USA). The column was a DB-WAX column (30 m × 0.25 mm, 0.25 µm; Agilent J&W Scientific, Folsom, CA, USA). The inlet temperature of the GC was kept at 240 °C. Helium (≥99.999%) was used as carrier gas with a constant linear velocity of 1.0 mL/min. 1-μL aliquot was injected in splitless mode. The temperature program that was optimized for GC was as follows: the initial oven temperature as 70 °C, held for 1 min; 20 °C /min to 150 °C; 10 °C/min to 190 °C; 3 °C/min to 220 °C; 5 °C/min to 230 °C; 230 °C held for 12 min. The MS conditions were as follows: electron impact mode at ionization energy of 70 eV; ion source temperature at 230 °C; transfer line temperature at 240 °C; full scan mode in m/z range 35–550 with 0.3 s/scan velocity. The solvent delay was 3 min.