Avoiding Regrettable Replacements: Can the Introduction of Novel Functional Groups Move PFAS from Recalcitrant to Reactive?
Folkerson et. al.
Environmental Science Technology
DOI: 10.1021/acs.est.3c06232
Together with our partner Aerodyne Research, we continuously support the operation of our mass spectrometers for new, groundbreaking research. This publication showcases the abilities of the Vocus 2R equipped with the Vocus Aim Reactor to help assess volatile per- and polyfluoroalkyl substances (PFAS) and their replacements.
PFAS are widely used in various industrial and commercial applications due to their chemical stability and water repellency. However, concerns about their environmental persistence and potential health impacts, such as endocrine disruption, have led to regulations banning long-chain PFAS. In response, industries are shifting to shorter-chain PFAS or new formulations like GenX and ADONA, which aim to reduce environmental impact while maintaining performance. Despite these efforts, many new replacements still exhibit significant environmental persistence. A recent development is TIVIDA, a new fluorinated surfactant designed to degrade more readily due to its multiple functional groups. TIVIDA breaks down into simpler fluorinated alcohols through ester cleavage, resulting in compounds like polyfluoroalkylether sulfide alcohol (FESOH). The environmental degradation of FESOH and similar compounds is being studied to understand how different functional groups affect degradation rates and products.
Using high-resolution iodide chemical ionization time-of-flight mass spectrometry (CI-TOFMS) and other analytical techniques, researchers aim to investigate how variations in PFAS structures influence their atmospheric transformation and persistence. This research seeks to improve the design of fluorinated chemicals to enhance their environmental degradability while maintaining their functionality.
To enhance degradation, new fluorosurfactant building blocks with various heteroatom linkages—ethers, thioethers, and polyfluorinated carbons—were developed, including FESOH, MeFESOH, ProFdiEOH, ProFEOH, and MeFdiEOH. These compounds were subjected to room temperature, gas-phase OH oxidation in an atmospheric chamber, with degradation monitored using high-resolution CI-TOFMS and UPLC-MS/MS. The thioether compounds FESOH and MeFESOH showed the highest oxidation rates, with rate constants of 2.82 and 2.17 × 10⁻¹² cm³ molecules⁻¹ s⁻¹, respectively. Oxidation products included ultrashort perfluoropropionic acid (PFPrA) and short polyfluoroether acids. Notably, MeFESOH showed potential for complete mineralization, indicating its promising environmental benignity.
This study highlights the importance of evaluating new PFAS replacements before market release to ensure they are degradable and environmentally sustainable. Results show that incorporating thioether groups into hydrofluoroether (HFE) alcohols significantly increases their degradation rate compared to ethers, reducing atmospheric lifetimes. Notably, while FESOH degrades relatively quickly, other compounds like MeFESOH can lead to complete mineralization or ultrashort polyfluorinated acids. Understanding how different functional groups affect PFAS degradation is crucial for developing environmentally friendly alternatives.
This study showcases the versatility and capabilities of the Vocus CI-TOF for PFAS detection and helping support research in PFAS replacements. Learn more about Vocus capabilities for PFAS detection in the whitepaper, Revolutionizing PFAS Detection in Air: High Sensitivity and Versatility with the Vocus Aim Reactor.
