Optimization and comparison of several extraction methods for determining perfluoroalkyl substances in abiotic environmental solid matrices using liquid chromatography-mass spectrometry

In this study, four extraction methods of perfluoroalkyl substances (PFASs) in soils and sediments were validated and compared in order to select the one that provides the best recoveries and the highest sensitivity. The determination of PFASs was carried out by liquid chromatography-tandem mass spectrometry. The extraction methods compared were based on (i) an aqueous solution of acetic acid and methanol (recoveries 44-125%, relative standard deviation (RSD) <25%), (ii) methanol (34-109%, <25%), (iii) sodium hydroxide digestion (24-178%, <49%), and (iv) ion pair (35-179%, <31%). The best results were obtained with methanol extraction, which recovered a greater number of PFASs and provided values between 45-103% in sediment and 34-109% in soil with RSDs <25% and limits of quantification (LOQs) between 0.02-0.31 and 0.01-6.00 ng g(-1), respectively. The selected method was successfully applied to Segura River sediments and soil samples taken near the Turia River. This study demonstrates the presence of PFASs in the studied rivers of the Valencian Community (0.07-14.91 ng g(-1) in Segura River sediments; 0.02-64.04 ng g(-1) in Turia River soils). Graphical Abstract Selected matrices and extraction methods for determination of perfluoroalkyl substances.This work has been supported by the Spanish Ministry of Economy and Competitiveness through the projects “Assessing and Predicting Effects on Water Quantity and Quality in Iberian Rivers Caused by Global Change (SCARCE)” (No. CSD2009-00065, http://www.scarceconsolider.es) and “Evaluation of Emerging Contaminants in the Turia River Basins: From Basic Research to the Application of Environmental Forensics (EMERFOR)” (GCL2011-29703-C02-02, http://mefturia.es). ML also acknowledges the Foundation “Tatiana Pérez de Guzmán el Bueno” for the grant to get the PhD and JC the VALi+d postdoctoral contract (APOSTD/2014/010) of the Generalitat Valenciana for funding.Peer Reviewe