1,700 compounds are in a class of volatile components
[7, 8]. These volatile compounds such as terpenoids,
fatty acid derivatives, indole and benzenoids play
important role for plant reproduction by attraction of
insects [9-11]. Moreover, isolated aroma compounds
are used as ingredients in perfume and food
industries [9]. The study of volatile compounds in
plants is performed by using solid phase
microextraction (SPME) which is a solvent-free
adsorption/desorption technique. It is applied in many
applications such as investigation of odor components
in foods and beverages [12, 13]. It consists of coated
fibers that are used to extract and concentrate target
compounds form the sample [12]. After extraction, the
fibers are transferred to analyze the target compounds
by gas chromatographic (GC)[12, 13]. Keene [13]
proposed the amount of analyte adsorbed by the fiber
depends on the thickness of the coating and on the
distribution constant of the analyte. The extraction
time is dependent on the period of time required to
obtain precise extractions for the analytes with the
highest distribution constants. Type of fiber is the
important key for improving the extraction efficiency
of SPME. Polarity of target compounds should be
similar to those coated on SPME fiber [13]. A thick
phase coat is the most suitable for extracting volatile
compounds, while a thin coat is the most effective for
adsorbing/desorbing semi-volatile compounds [12]. It
has gained widespread acceptance in many areas in
recent years [14-16].