Qualitative analysis was conducted using a Hewlett–Packard
Gas Chromatograph Model 5890 series II (Hewlett–Packard, Palo
Alto, CA, USA), coupled with a Hewlett–Packard Model 5972 Mass
Selective Detector. Separation was conducted in a polyethylene
glycol FFAP (50 m×0.2 mm ID×0.33 m film thickness) capillary
column. Injector and mass spectrometer (MS) interfaces were
processed at 250 ◦C and 280 ◦C, respectively