2.2. Chemical characterization of the oil
The chemical composition of the extracted oil was determined
by gas chromatography (GC) and gas chromatography–mass spectroscopy
(GC–MS) as per Singh et al. (2009). Briefly, GC was
performed on a Shimadzu GC-17A Gas Chromatograph fitted with
a flame ionization detector (FID), equipped with DB-5 column
(60m×0.25mm, i.d.; 0.25m film thickness), and using helium
(He) as carrier gas (split ratio 1:20; flow rate 1mlmin−1). The oven
temperature was programmed from 50 ◦C (held initially for 2min)
to 260 ◦C (held for 3min) at 4 ◦Cmin−1. Relative percentages of
different constituents were calculated from peak area of total ion
chromatograms without any correction factor. The data presented
are mean percentages of three analyses.