analysis was carried out using a gas chromatograph (PerkinElmer
Clarus 500) with a 250 lmdiameter and 30 mlong Elite-5 capillary
column (5% phenyl/95% dimethylpolysiloxane) equipped with a
mass selective detector in the electron ionization mode. About
2 lL of the sample was injected for the analysis. Helium was used