Characterization of PFAS Chemicals in Anti-Fog Solutions Using Gas Chromatography, and High-Resolution Time-of-Flight Mass Spectrometry

Significance of the Topic

Per- and polyfluoroalkyl substances (PFAS) are widely used in consumer and industrial products for their water-, stain- and fog-resistant properties. Their environmental persistence, mobility and potential health risks make accurate identification and quantification essential for laboratory quality control, regulatory compliance and environmental monitoring.

Objectives and Study Overview

The study aimed to assess PFAS contamination in commercial anti-fog solutions. By combining gas chromatography with high-resolution time-of-flight mass spectrometry (GC-TOFMS and GC-HRTOFMS), the research targeted both known PFAS compounds and unknowns in five anti-fog spray formulations.

Methodology

• Sample preparation: 100 µL of each anti-fog solution diluted to 1 mL with acetone and vortexed.
• Instrumental analysis: Non-targeted automated data acquisition including peak finding, deconvolution, library searches and accurate mass calculations.
• Ionization modes: Electron impact (EI) and positive chemical ionization (PCI) for complementary fragmentation information.
• Data processing: Automated spectral matching, mass delta evaluation and retention index comparison against hydrocarbon standards.

Instrumentation Used

• Gas Chromatograph: Agilent 8890 with Rxi-5ms columns.
• Time-of-Flight Mass Spectrometer: LECO Pegasus BTX for GC-TOFMS and Pegasus HRT+ for GC-HRTOFMS.
• Acquisition parameters: Mass range m/z 50–1400, resolution up to 50 000, acquisition speed up to 500 spectra/s.

Key Findings and Discussion

• Known PFAS identification: Detected 6:2, 8:2 and 10:2 fluorotelomer alcohols (FTOH) and N-MeFOSA with high mass accuracy (≤0.2 ppm).
• Unknown PFAS characterization: Peaks 6–14 corresponded to a homologous series of fluorotelomer ethoxylates (FTEOs) and other novel fluorinated species.
• Analytical challenges: Diverse PFAS chemistry, incomplete spectral libraries and lack of commercial standards addressed through high-resolution accurate mass and dual ionization strategies.

Benefits and Practical Applications

The combined GC-TOFMS and GC-HRTOFMS workflow enables comprehensive profiling of PFAS in consumer products. It supports QA/QC in manufacturing, forensic screening of formulations and environmental fate studies of fluorinated chemicals.

Future Trends and Opportunities

• Expansion of high-resolution databases and spectral libraries for emerging PFAS.
• Integration with liquid chromatography techniques and negative chemical ionization for polar PFAS derivatives.
• Application of suspect and non-target screening workflows coupled with machine learning to enhance unknown annotation.
• Development of isotopically labeled standards and harmonized retention index frameworks for interlaboratory comparability.

Conclusion

The study demonstrates that advanced GC-HRTOFMS methods effectively characterize both targeted and novel PFAS in anti-fog products. High mass accuracy, complementary ionization and automated data processing overcome key analytical obstacles, delivering a robust approach for PFAS monitoring.

References

Hayes J, Humston-Fulmer E, Alonso DE, Binkley JE. Characterization of PFAS chemicals in anti-fog solutions using gas chromatography and high-resolution time-of-flight mass spectrometry. LECO Corporation.