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.

Perfluoroalkyl Compounds

“…The 8:2 and 10:2 FTUCAs (concentrations up to 15.1 ng/L) were observed in samples collected from four lakes in the Canadian Arctic [166]. In addition, a method for the extraction and analysis of FTOHs in water has also been developed by Szostek, Prickett and Buck [184], but it has yet to be applied to real-life samples.…”

CASMI 2013: Identification of Small Molecules by Tandem Mass Spectrometry Combined with Database and Literature Mining

“…However, accurate mass fragment and neutral loss analysis conclusively provided the formula C 12 is was submitted as the lead candidate with high con dence (Score= 0.90) along with two equally consistent but less common alkyl isomers (assigned lower scores).…”

“…A reference negative ion electrospray CID tandem mass spectrum for 8-2 uorotelomer alcohol was found that matched the provided data very well. 12) A er a SciFinder search of the formula to investigate potential isomers, 8-2 uorotelomer alcohol was Fig. 4.…”

Perfluorinated Compounds’ Analysis, Environmental Fate and Occurrence: The Llobregat River as Case Study

“…Therefore, it is recommended to avoid headspace in sampling bottles [51], and kept samples at low temperature after collection [44,45,52]. Szostek et al studied the stability of PFTOHs in water under different storage conditions [53]. In this work it was concluded that aqueous samples can safely be stored in the freezer using glass vials and sealed with a septum lined with alumina foil.…”

“…In this work it was concluded that aqueous samples can safely be stored in the freezer using glass vials and sealed with a septum lined with alumina foil. In addition, no biodegradation or biotransformation was observed under these conditions [53]. On the other hand, also it was studied the possible benefices associated with the use of biological inhibitors (such as formalin) to preserve the samples, but it was found that some suppress the MS responses during the analysis [54], and therefore should be avoided.…”