Liquid extraction is one of the oldest techniques used for preparation of
samples for accelerants analysis. However, a survey of methods used by participants
of interlaboratory quality control testing shows that it is still commonly
used in analytical laboratories. In fact its popularity seems to have
grown in recent years. This is because the head-space method is often not
very successful in the case of compounds with high boiling points that are
strongly bound to the matrix [3]. Then applying the extraction method improves
the situation. If preliminary head-space analysis indicates the presence
of products in the oil category, then liquid extraction is used. According
to many analysts, it is also the most appropriate method for aqueous samples
analysis. The extract gained is usually subjected to filtration and additional
treatment, with the aim of concentrating analytes and possibly decreasing
the amount of interferents.