at 70 C for 3 min, increased to 110 C at
a rate of 10 C min1 and raised to 200 C at 30C min1 and kept at
this temperature for 3 min. The injector temperature was set at
240 C and all injections were carried out on the splitless mode for
3 min. The mass spectrometer (MS) was operated in the electron
ionization (EI) mode (70 eV) and helium (99.999%) was employed
as carrier gas and its flow-rate was adjusted to 1mL min1.