Identification of the volatile compounds was
carried out by matching
the unknown mass spectra with those provided by the library mass spectra (National Institute of Standards & Technology library — NIST 05), comparison of the experimental and Kovats Indices (KI) from the literature
(Acree & Arn, 2013; Adams, 1995; Jennings & Shibamoto, 1980) and by
the elution order of compounds. A series of n-alkanes (C6–C24) was analyzed under the same conditions to obtain the KI values.