Are (fluorinated) ionic liquids relevant environmental contaminants? High-resolution mass spectrometric screening for per- and polyfluoroalkyl substances in environmental water samples led to the detection of a fluorinated ionic liquid

Abstract

Fragmentation flagging (FF), a high-resolution mass spectrometric screening variant that utilizes intentionally produced indicative in-source fragments, was used to screen for per-and polyfluoroalkyl substances (PFASs) in surface waters. Besides expected legacy PFAS, FF enabled the detection of some rarely investigated representatives, such as trifluoromethanesulfonic acid (TFMSA). Additionally, a novel PFAS was detected and identified as tris(pentafluoroethyl)trifluorophosphate (FAP) via MS/MS experiments and confirmed with a reference standard. The first monitoring of FAP in 20 different surface waters revealed a localized contamination affecting three connected rivers with peak concentrations of up to 3.4 μg/L. To the best of our knowledge, this is the first time FAP has been detected in environmental water samples. The detection of FAP, which is exclusively used as a constituent of ionic liquids (ILs), raises questions about the environmental relevance of ILs in general and particularly fluorinated ILs. A following comprehensive literature search revealed that ILs have already been intensely discussed as potential environmental contaminants, but findings reporting ILs in environmental (water) samples are almost non-existent. Furthermore, we address the relevance of ILs in the context of persistent, mobile, and toxic chemicals, which are at present gaining increasing scientific and regulatory interest, and as part of the PFAS "dark matter" that represents the gap between the amount of fluorine originating from known PFAS and the total adsorbable organically bound fluorine. Keywords (Fluorinated) ionic liquids . PFAS . HRMS . Fragmentation flagging . PM(T) substances Published in the topical collection Persistent and Mobile Organic Compounds -An Environmental Challenge with guest editors Torsten C.

Ultra-Short-Chain PFASs in the Sources of German Drinking Water: Prevalent, Overlooked, Difficult to Remove, and Unregulated

“…Currently, the lack of occurrence data makes it impossible to evaluate if its use in energy storage leads to its environmental release. NTf 2 and the infrequently detected FAP (five samples, median 0.5 ng/L, maximum 0.7 ng/L) have only recently been detected in the aquatic environment as a novel class of PFASs. Occurrence data on NTf 2 is so far exceedingly scarce and only semiquantitative .…”

Flexibility is the key to tuning the transport properties of fluorinated imide-based ionic liquids

“…This is especially important in the light of recent reports indicating that some uorinated anions are persistent environmental contaminants. [41][42][43][44] The insights in this work provide a starting point for the research on novel anions with lowered uorine content without having to compromise on ionic liquid performance.…”

Water Analysis: Emerging Contaminants and Current Issues

“…In a particularly interesting discovery, Neuwald et al reported the first fluorinated ionic liquid found in environmental waters. 48 Ionic liquids are often considered "green" solvents because they have negligible vapor pressure, but many are known to be toxic. This fluorinated ionic liquid was structurally identifi ed as tris(pentafl uoroethyl)trifluorophosphate (FAP) using HRMS/MS and was confirmed with an authentic standard.…”