Determination of polycyclic aromatic hydrocarbons (PAHs) in aqueous samples by HPLC-FLD with salting-out liquid-liquid extraction

Polycyclic aromatic hydrocarbons (PAHs) are a group of more than 100 different chemical substances, which contain two, or more fused aromatic rings most of them toxic or carcinogenic. In this study, the Quechers extraction conditions were adapted to perform the extraction of aqueous samples. Quechers has become a standard technique for the analysis of pesticides and other organic substances. Its simplicity and low cost have made it popular in laboratories around the world for processing samples such as fruits and vegetables. The success of this method on solid samples contrasts with the advances in the extraction of aqueous samples where tedious steps of extraction, concentration and solvent changes must be carried out prior to the instrumental analysis. A methodology for the liquid-liquid extraction (water/acetonitrile) of 15 PAHs in aqueous matrices was developed. The mixture was saturated with anhydrous sodium sulfate to cause the partitioning and the extract was analyzed by High-Resolution Liquid Chromatography with Fluorescence Detection (HPLC-FLD). The recoveries of analytes achieved (61-114%) were comparable to those expected using traditional extraction techniques, and with moderate uncertainty. The results were consistent with the expectations for of the required analytical and concentration ranges.