LRI of the sample components were determined on the basis of the retention times of a mixture of homologue n-alkanes C6- C44 under the same GC/MS operating conditions. The value of retention indices were calculated according to the equation proposed by Vandendool & Krantz (1963). Pure standards and homologue n-alkanes C6-C44 were purchase from Sigma Aldrich Co S.r.l Milan Italy. GC-MS Solution Ver.1.10 (Shimadzu, Japan) software allowed to measure, automatically the experimental LRI.