different
extraction efficiencies for various compounds with
various extracting agents, and low sensitivity. The
sensitivity of LLE methods can be increased by
removing part of the extracting solvent by heat or
by a stream of an inert gas. This step, however, can
lead to losses of analytes, and safety hazards
involved in handling toxic and inflammable solvents
are not negligible. Frequently, the whole
LLE procedure is tedious, time consuming and
costly [6]. Thus, much interest has been recently
focused in repairing conventional solvent extraction
methods for isolating environmental pollutants
with SPE techniques.