Trifluoromethanesulphonic acid

Monitoring data

Administrative data

Endpoint:

monitoring data

Type of information:

experimental study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Data source

Reference

Reference Type:

publication

Title:

Halogenated methanesulfonic acids: A new class of organic micropollutants in the water cycle

Author:

Daniel Zahn, Tobias Fromel, Thomas P. Knepper

Year:

2016

Bibliographic source:

Water Research 101 (2016) 292-299

Materials and methods

Principles of method if other than guideline:

In this study mixed-mode solid phase extraction (SPE) enrichment in combination with HILIC-HRMS non-target screening was deployed to analyse nineteen water samples form five European countries and different compartments of the water cycle. The focus of this work was the identification of mobile and persistent contaminants that may impact raw and drinking waters and are thus of concern for human health.

GLP compliance:

no

Type of measurement:

background concentration

Media:

other: Urban effluent, surface water, ground water and drinking water.

Study design

Details on sampling:

Water Samples
Nineteen water samples were collected from five European countries (France, the Netherlands, Switzerland, Germany and Spain) and different compartments of the water cycle (urban effluent (UE), surface water (SW), ground water (GW) and drinking water (DW)) in the time period from spring to summer 2015 and anonymized. Samples were named with a two letter code indicating the sample type and a consecutive number. All samples were grab samples and not treated in any way before enrichment. Detailed information about the samples cannot be given due to confidentiality reasons. Two sampling points (one surface water and one drinking water sampling point, used as quality control) were sampled again in February 2016, and a sampling blank consisting of mineral water was prepared in parallel to these samples. The drinking water sample DW-19 was also taken in February.

Results and discussion

Details on results:

In the figure 3 of the publication the following elements are graphically reported for approximated concentrations of trifluoromethanesulfonic acid in environmental water samples. :
- urban effluent : 10-100 ng/L
- surface water : from 1 to > 1000 ng/L
- ground water : 1-100 ng/L
- drinking water : from below 1 to 1000 ng/L.

The variety of aqueous compartments in which F3-MSA was detected implies persistence and mobility in the water cycle.

Any other information on results incl. tables

Identification of trifluoromethanesulfonic acid

An unknown compound with an m/z of 148.9526 and a retention time of 1.95 min was prioritized since it was detected in the majority of the samples (84%) and was among the highest intensity signals that could not be attributed to an inorganic anion. Visual inspection of the mass spectrum led to the exclusion of chlorine and bromine (no m/z +2 Da of sufficient intensity) for composition elucidation. The presence of one sulphur atom in the molecule was indicated by an m/z +2 Da signal with approximately 4.5% relative intensity. Two m/z +1 signals were detected, one with m/ z + 0.9991 and a relative intensity of 0.6%, which was attributed to the 33S isotopologue and thus confirmed the presence of sulphur in the molecule, and the other one with m/z + 1.0030 and a relative intensity of 0.8% which indicated a low number of carbon. Based on these observations, C (1-2), H (0-20), O (0-10), N (0-10), S (exactly 1), F (0-10) and P (0-10) were selected for elemental composition calculation. With these restrictions, only one hit was found for a singly negatively charged ion within a maximal allowed deviation of 5 ppm from the calculated exact mass. The elemental composition of feature m/z 148.9526, tR = 1.95 was found to be CF3SO3 -. A Chemspider (www.chemspider.com) query for CF3SO3H and CF3SO3 resulted in only two structures that were in compliance with the observed ionization behaviour, tri- fluoromethanesulfonic acid and trifluoromethyl hydrogen sulphite or their respective anions. MS² measurements were performed to facilitate structural elucidation of the detected compound. Three fragments were observed for m/z 148.9526 : SO2 and SO3 radical anions, which are characteristic fragments of sulfonic acids, and FSO3 , which is characteristic for fluorinated sulfonic acids. Therefore, the substance was tentatively identified as trifluoromethanesulfonic acid (F3 -MSA). Subsequently, a certified standard of F3-MSA was purchased and analysed. Retention time, isotopic pattern and all three fragments were in compliance with the reference material which led to the confirmation of the proposed structure.

To assess the relevance of halogenated methanesulfonic acids (HMSAs) in the environment, concentrations of all detected HMSAs were estimated by calibration with F3-MSA, the only investigated substance with an available reference standard. When evaluating the concentrations for F3-MSA, it is evident that this substance is present in all compartments of the water cycle, ranging from urban effluent to drinking water, and may be found in concentrations up to the mg/L range.

Quality control

Two sampling points (SW-01 and SW-03) were sampled twice, once in September 2015 (a) and once in February 2016 (b). In parallel with the second sampling mineral water was prepared as sampling blank and treated analogously to the samples (same bottles, same rinsing procedure of the bottles, same storage conditions and same sample preparation). By comparison of the September 2015 and February 2016 samples from these two locations the presence of all initially detected analytes could be confirmed with estimated concentrations often differing by a factor less than two for higher concentration contaminants (F3-MSA and Cl2-MSA for SW-01 and F3-MSA, Cl2-MSA, BrCl-MSA and Br2-MSA for DW-03). This indicates that these substances are not onetime contaminants caused by a random event (e.g. spillage) but rather consistently present in the water cycle.

The sampling blank shows little to no contamination with chlorinated and brominated MSAs and the estimated F3-MSA concentration in the blank is less than 5% of those in the corresponding samples (SW-01b and DW-03b), which proves that the contamination of the samples must arise from the water samples themselves and is not process related. While the low level contamination of the sampling blank with F3-MSA may originate from the used glass bottles or the washing procedure the sample preparation can be excluded as origin of the F3-MSA contamination since a laboratory blank (200 mL ultrapure water) that was prepared in parallel showed no signal for F3-MSA. Due to the limited knowledge about the occurrence of F3-MSA, however, it may also be possible that the mineral water itself is contaminated with F3-MSA.

Applicant's summary and conclusion

Conclusions:

Trifluoromethanesulfonic acid was found in samples of aqueous compartments.