Supercritical fluid extraction of organochlorine pesticides and some metabolites in frogs from National Park of Ordesa and Monte Perdido Original Research Article

The optimization of supercritical fluid extraction (SFE) with CO2 for the extraction of a series of organochlorine pesticides (OCPs) and some metabolites in biota samples (frogs) from the National Park of Ordesa and Monte Perdido (Spain) and further analysis by GC–electron capture detector (ECD) is carried out. An experimental design is applied to the optimization of SFE. The Soxhlet extraction of the same samples is optimized too, together with the necessary clean-up step using four different solid cartridges. The analytical procedures as well as the results obtained are compared. Seven in sixteen OCPs under study showed recovery values above 80%, when using Soxhlet while nine OCPs were over 80% in the case of SFE. The analysis of frog samples showed values below 7 ng/g on the basis of dry matter for all the OCPs under study. The analytical procedures as well as the results obtained in real samples are discussed.