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of environmental contaminants in soil and water samples.

Extraction from Soil Sample

Extraction methods from solid samples include the shaking extraction method, the soxhlet extraction
method and the supersonic extraction method, all of which use the appropriate solvent for analytes.
Recently, the super critical fluid extraction (SFE) method which is applied for chemical compounds
having vapor pressure at a specific temperature and pressure changing into the state for super critical
fluid for extraction has been used. For more information on this method, refer to the reviews [10,11]. In
either of the above methods, it is important to investigate the collected results in detail and select an
appropriate solvent.

The extracted solution is often further processed as a liquid sample and is rarely subjected to direct
analysis, except in the case of some highly volatile contaminants.

Liquid-Liquid Extraction

This method employs shaking extraction mainly on aqueous samples in a non-mixing solvent in order
to transfer target compounds into the solvent. It is necessary to select the solvent to be used according
to the polarity of the target compounds and to improve recovery by saltingout etc. The extracted
solution is subjected to the clean-up operation either directly or following concentration, or is subjected
to GC or LC for separation and detection directly or following concentration and derivatization.

Recently, the solid phase extraction (SPE) method, as described below has prevailed due to the
following defects of the liquid-liquid

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