In recent years perfluorinated alkylated substances (PFAS) have appeared as a new class of global pollutant. Besides being an industrially important group of compounds, PFAS are regarded as highly toxic and extraordinarily persistent chemicals that pervasively contaminate human blood and wildlife throughout the world. They are therefore regarded as PBT (persistent, bioaccumulative, and toxic) chemicals. Two comprehensive methods have been developed for determination of eleven of the most environmentally relevant PFAS (seven perfluoroalkylcarboxylates, two perfluoroalkylsulfonates, and two perfluoroctanesulfonamides) in aqueous samples. The compounds were isolated by liquid-liquid extraction (LLE) and solid-phase extraction (SPE), and identification and quantification of the target analytes were achieved by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS-MS). With LLE detection limits ranged from 0.26 to 0.62 ng L(-1) for enrichment of 900-mL water samples; recovery of PFAS with a carbon chain longer than C7 was excellent (80-93%). With SPE, carboxylates with carbon chains <C10 could be extracted efficiently (70-98%) under acidic conditions, and PFOS and PFOSA could be extracted efficiently (81% and 96%, respectively) under basic conditions, resulting in MDLs between 0.25 and 0.64 ng L(-1). The LLE method was applied successfully to Austrian wastewater effluent samples.