The ionic liquid 1-hexadecyl-3-methylimidazolium bromide as novel extracting system for polycyclic aromatic hydrocarbons contained in sediments using focused microwave-assisted extraction

A method to extract PAHs from sediments is carried out using aqueous solutions containing aggregates of the ionic liquid (IL) 1-hexadecyl-3-methylimidazolium bromide (HDMIm-Br) as the extracting medium. Focused microwave-assisted extraction has been used to accelerate the extraction step, followed by HPLC with fluorescence detection without clean-up steps to remove the IL prior to injection. The method has been applied to certified reference sediment BCR-535 and marine sediments from Tenerife (Canary Islands) with successful results. The optimized method gave average absolute recoveries of 91.1% for six of the seven PAHs studied, with relative standard deviations lower than 10.4%. The overall method is characterized for presenting low extraction times (6 min), low amounts of the sediment (0.1 g), low amounts of IL (45 mM), and low volumes of aqueous extractant solution (9 mL). The use of small amounts of both IL and aqueous extractant solution allows the method to be considered environmental-friendly.