Static extraction with modified pressurized liquid and on-line fluorescence monitoring: Independent matrix approach for the removal of polycyclic aromatic hydrocarbons from environmental solid samples

The coupling of a static pressurized liquid extractor to a flow injection manifold has allowed real-time on-line fluorescence monitoring of the polycyclic aromatic hydrocarbons (PAHs) extracted from environmental solid samples, which can be used for either screening or semiquantitative purposes. Sodium dodecyl sulfate (SDS) was added to the water for favoring the extraction of the low-polar analytes. Different solid samples such as sandy soil, river sediments, trout and sardine spiked with the target PAHs were subjected to several 15-min static extraction cycles with SDS–water, at 200 °C. The results obtained demonstrated that fluorometric monitoring of static pressurized liquid extraction constitutes an approach as efficient as conventional Soxhlet for the extraction of PAHs from solid samples but with the following positive features: (a) drastic reduction of the extraction time as the extraction kinetics can be monitored and thus the end of the leaching step determined independently of the sample matrix; (b) use of water as extractant thus given place to an environmentally friendly method; and (c) coupling of static extraction to subsequent dynamic steps. The method has been applied to a certified reference material (CRM 524, BCR, industrial soil/organics) for quality assurance/validation. The total content of each analyte was determined by HPLC–fluorimetric detection.