GC-MS analyses were carried out under the following conditions. Temperatures of injector and ion source: 250 °C and 200 °C, respectively; carrier gas: He; flow control mode: constant linear velocity; flow rate: 0.6 ml/min; injection split ratio: 1:50. Oven temperatures were programmed as follows: the temperature was raised from 50 °C to 240 °C at 8 °C/min rate and then was kept constant during 15 min. The mass spectrometer was operated in electron ionization (EI) mode at 70 eV, scan rate: 1666 units/s, mass range: 44-500 m/z.