Identifying Unknown Fluorine-Containing Compounds in Environmental Samples Using ¹⁹F NMR and Spectral Database...

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Spectroscopy

Background:

• Per- and polyfluorinated alkyl substances (PFAS) are ubiquitous environmental contaminants.
• Current analytical methods like mass spectrometry often fail to detect a significant portion of fluorinated compounds.
• This gap hinders accurate assessment of total fluorine in the environment.

Purpose of the Study:

• To demonstrate the utility of fluorine-19 Nuclear Magnetic Resonance (19F NMR) spectroscopy for identifying and quantifying previously undetected PFAS.
• To develop a comprehensive 19F NMR database for fluorinated compounds.
• To apply 19F NMR to determine PFAS concentrations in a real-world contaminated site.

Main Methods:

• Acquisition and compilation of 19F NMR spectra for hundreds of fluorinated compounds.
• Construction of a searchable 19F NMR spectral database.
• Analysis of an aqueous firefighting foam-contaminated site sample using the developed 19F NMR database to quantify PFAS.

Main Results:

• Successfully utilized 19F NMR to identify and quantify PFAS in an environmental sample.
• The developed 19F NMR database significantly aids in the analysis of complex fluorinated mixtures.
• Demonstrated the potential of 19F NMR to improve the mass balance of total fluorine in environmental monitoring.

Conclusions:

• 19F NMR is an unbiased and effective analytical tool for characterizing diverse PFAS, overcoming limitations of traditional methods.
• The created 19F NMR database is a valuable resource for researchers studying PFAS.
• This approach enhances the ability to accurately assess environmental contamination by PFAS.