then to 280 ◦C at 10 ◦C/min, ending with 10 min at 280 ◦C. The carrier gas was He at a flow rate of 1.0 ml/min
and the split mode had a ratio of 1:20. The injection port was set at 225 ◦C. Significant quadrupole MS operating parameters: interface temperature 240 ◦C; electron impact ionization at 70 eV with scan mass range of 40–350 m/z at a sampling rate of 1.0 scan/s. Constituents were identified by computer search using digital libraries of mass spectral data (NIST, 1998) and by comparison of their retention indices and authentic mass spectra (Adams, 2007), relative to C8–C32 n-alkane series in a temperature-programmed run (Van Den Dool and Kratz, 1963).