An Agilent Technologies
6850 series II gas chromatographer was used. The gas
chromatographer was equipped with a HP-5MS capillary column
J.M. Naranjo et al. / Bioresource Technology 133 (2013) 38–44 39
(25 m length, 0.32 mm internal diameter). Helium (velocity at
5 cm/min) was used as the carrier gas