IC-MS/MS analysis of trifluoroacetic acid according to DIN 38407-53

Importance of the Topic

Trifluoroacetic acid (TFA) is a persistent, highly mobile breakdown product of PFAS that accumulates in surface water, groundwater, precipitation and even biota. Its resistance to conventional treatment and growing environmental concentrations have raised concerns among regulators and analytical chemists, prompting the need for reliable monitoring methods.

Study Objectives and Overview

This application note presents a validated protocol for quantifying TFA in water at trace levels (0.1–3.0 μg/L) based on the German standard DIN 38407-53. The method was tested across 12 laboratories in Germany and Switzerland to ensure reproducibility and compliance with regulatory requirements.

Methodology

Sample handling involved eight real and spiked water matrices stored at 4 °C and analyzed within seven days. No further sample preparation was required as standards and samples were directly injected (100 μL) onto an anion-exchange column. Separation employed isocratic elution with 5 mmol/L Na2CO3, 0.2 mmol/L NaHCO3 and 10 % methanol. Detection used electrospray ionization tandem mass spectrometry in dMRM mode (m/z 113→69, 65 V fragmentation). Calibration spanned 0.2–4.0 μg/L (extended to 6.0 μg/L) with R² = 0.9998.

Instrumentation

• Metrohm 940 Professional IC Vario TWO with sequential suppression and peristaltic pump
• 889 IC Sample Center – cool for temperature-controlled sample handling
• Metrosep A Supp 17-150/4.0 separation column with Metrosep RP 2 Guard/3.5
• Agilent 6475 triple quadrupole mass spectrometer controlled by MagIC Net and MassHunter software

Main Results and Discussion

Calibration accuracy ranged from 98.1 % to 110.1 % with a limit of detection of 0.017 μg/L and quantification of 0.062 μg/L (DIN 32645). Triplicate analyses yielded relative standard deviations below 2 %. Recoveries for spiked samples at 1.18 μg/L and 2.87 μg/L were 109 % and 102 %, respectively. Retention time stability was better than 0.1 min at 8.2 min.

Benefits and Practical Applications

The IC-MS/MS approach offers high matrix tolerance, minimal sample preparation, robust column life and fully automated sampling. It provides a validated alternative to reversed-phase LC methods for monitoring ultra-short-chain PFAS in environmental and drinking water.

Future Trends and Opportunities

Emerging applications may include online monitoring of TFA and related PFAS, expansion to other short-chain fluorinated acids, integration with non-target screening workflows, and further automation for high-throughput environmental surveillance.

Conclusion

The described IC-MS/MS method fulfills the performance criteria of DIN 38407-53, delivering sensitive, accurate and reproducible quantification of TFA in diverse water matrices. Its automated features and validated interlaboratory performance support its adoption for routine PFAS monitoring.

References

1. DIN. DIN 38407-53: German standard methods for the examination of water, wastewater and sludge – Part 53: Determination of trifluoroacetic acid (TFA) by LC-MS/MS, 2024.
2. Dorgerloh U., Becker R., Freeling F. et al. Standardising the quantification of trifluoroacetic acid in water: interlaboratory validation trial using LC-MS/MS. Accreditation Qual. Assur. 2025.
3. DIN. DIN 32645:2008-11: Chemical analysis – Decision limit, detection limit and determination limit under repeatability conditions – Terms, methods, evaluation, 2008.