Carla Frege
TOFWERK Switzerland
Introduction
Polyfluoroalkyl substances (PFAS) are a large and diverse group of compounds that are widely used in industry to make fluoropolymer coatings used in non-stick cookware, fire retardants, stain and water repellents, furniture, waterproof clothing, pizza boxes and take-out containers, food packaging, carpets and textiles, rubbers, plastics, electronics, dental floss, and other products. These compounds have recently come under scrutiny from regulatory and health agencies because they last an extremely long time in the environment, can travel and transfer from one system to another [1], and may cause serious health effects [2]. These substances are increasingly critical to measure because even exceptionally low concentrations (ppt level) may be relevant to environmental and health interests. Measuring low concentrations with varying structures and identities presents a challenge for traditional instrumentation.
Sensitive PFAS Detection
TOFWERK’s API-TOF with iodide reagent ion chemistry has been shown to detect PFAS compounds with remarkably high sensitivity [3]. Recently, we noticed PFAS signal in samples measured with the Vocus Aim CI-TOF; including ambient air samples from an industrial facility, and headspace samples from cosmetics and food packaging.
Figure 1 shows the mass spectral peaks of several PFAS detected in the headspace of mascara. The PFAS compounds are detected as the parent molecule M clustered with the iodide reagent ion (M•I-). The molecular identity is based on the chemical formula determined from precise mass-to-charge ratio measurement and confirmed using isotope patterns. Because of their high halogen content, PFAS have a unique mass spectral signature.
Figure 2 shows comparison of PFAS signals in industrial air, waterproof mascara sample headspace, and popcorn sample headspace.
References
- ITRC (Interstate Technology & Regulatory Council). PFAS Technical and Regulatory Guidance Document and Fact Sheets PFAS-1: Environmental Fate and Transport Processes, 2021. https://pfas-1.itrcweb.org/5-environmental-fate-and-transport-processes/
- Pelch et al. PFAS Database available at https://pfastoxdatabase.org/, 2021. DOI: 10.17605/OSF.10/F9UPX
- Riedel et al. Gas-Phase Detection of Fluorotelomer Alcohols and Other Oxygenated Per- and Polyfluoroalkyl Substances by Chemical Ionization Mass Spectrometry. Environ. Sci. Technol. Lett., 2021. DOI: 10.1021/acs.estlett.9b00196
