Sample carrier with PFAS-containing environmental samples and consumer products, (r.) ultra-high vacuum cell of the synchrotron beamline "Phoenix II" at the Swiss Light Source.
Source: Christian Vogel
Per- and polyfluoroalkyl substances (PFAS) have emerged as a global contaminant over the past 20 years. Over the last few decades, increased production, consumption, and disposal have led to wider distribution of PFAS in the environment, resulting in a steady increase in the number of reported contaminated sites worldwide. Due to current regulations and restrictions on the production of long-chain, more persistent PFAS, industrial suppliers have shifted production to short-chain, less persistent, but still hazardous alternatives. The development of novel analytical approaches is essential to track the rapid evolution and proliferation of these compounds in environmental media. Typically, analytical studies require sample extraction or destruction. For our investigations, we used micro-X-ray fluorescence (XRF) mapping combined with fluorine K-edge X-ray absorption near-edge structure (XANES) spectroscopy as well as liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) to analyze PFAS contamination in soils, sewage sludge, and various consumer product samples. Using intense X-ray radiation from the synchrotron source, it was possible to visualize the presence of organofluorinated chemicals by tracing a fluorine elemental specific map. In the next step, fluorine K-edge micro-XANES spectroscopy was used to verify fluoroorganic compounds in concentration ranges down to 100 µg/kg. The method allows separation from inorganic fluorides but is limited when identifying individual PFAS. Simultaneous LC-MS/MS analysis of all samples revealed the presence of several perfluorinated carboxylic- and sulfonic acids, which further supports the results of the imaging XRF method. Therefore, the method, although synchrotron-based, can contribute to further important analytical investigations in the global PFAS problem.
Taking a Look at the Surface: µ-XRF Mapping and Fluorine K-edge µ-XANES Spectroscopy of Organofluorinated Compounds in Environmental Samples and Consumer Products
Philipp Roesch, Christian Vogel, Philipp Wittwer, T. Huthwelker, C. Borca, Thomas Sommerfeld, Stephanie Kluge, Christian Piechotta, Ute Kalbe, Franz-Georg Simon
published in Environmental Science: Processes & Impacts, pages 1-12