Determination of fluorotelomer alcohols by liquid chromatography/tandem mass spectrometry in water

Abstract

Fluorotelomer alcohols (FTOHs) are important polyfluorinated raw materials that belong to the general category of perfluoroalkyl substances (PFAS). PFAS, including perfluoroalkyl carboxylates (PFCAs) and perfluoroalkyl sulfonates, have recently attracted considerable attention because they are persistent and found globally in the environment. FTOHs are precursors that may degrade in the environment to PFCAs. The development of analytical methods for determination FTOHs in environmental samples is necessary to determine the environmental presence of FTOHs. This work presents the development and validation of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of FTOHs (6-2, 8-2, 10-2) in aqueous samples. Chromatographic conditions were optimized in order to obtain focused FTOH chromatographic peaks. The mobile phase and mass spectrometric conditions were optimized to enable formation of deprotonated FTOH molecules in the negative ion electrospray mode. Two extraction methods were investigated using acetonitrile and methyl tert-butyl ether (MTBE). These methods were validated for a range of environmental water samples fortified with FTOHs at three different levels. Both extraction methods resulted in recoveries from 70 to 120%. Detection limits of FTOHs were estimated to be approximately 0.09 ng/mL for LC/MS/MS detection. An LC/MS method was also developed for FTOH determination with an estimated 1.2 ng/mL limit of detection. Various sample storage scenarios were investigated. It was determined that the aqueous samples of FTOHs are best preserved by storing them frozen in sealed vials with aluminum foil lined septa.