GC=MS
Analysis An Agilent gas chromatograph 5973 series equipped with a DBWAX analytical fused-silica column (30 m 3 0.25 mm 3 0.25 lm film thickness from J&W Scientific, Folsom, CA) coupled with 5989A mass selective detector, was used. Compounds were injected by thermal desorption at 250C during 5 min in the injector in a splitess mode. The oven temperature was held at 40C for 5 min, ramped to 250C at a rate of 4C/min and maintained at 250C for 10 min. The carrier gas was Helium 6.0 (Air Product), with a flow-rate of 1.5 mL/min. The electron impact (EI) energy was 70 eV and the quadrupole temperature was set at 250C. Detection was carried out in full scan mode covering a mass range (m/z) of 50–450 amu.