Robust detection of per- and polyfluoroalkyl substances (PFAS) congeners in different matrices and samples is a must. Scenarios scientists report on the current state of the art in measuring PFASs in environmental matrices and complex samples.
In the framework of the SCENARIOS project, the University of Piemonte Orientale (UPO) is working on the development of innovative analytical methods for the detection and monitoring of PFAS in different environmental media (groundwater, surface water, wastewater, soil, sediment, biosolids) and biological media (human blood, serum, urine, animal fluids, etc.). It is worth noting that PFAS are a very large class of synthetic chemicals widely used in industrial processes and consumer products. Their chemistry is complex and there are thousands of variants in commerce and the environment. There is evidence that some PFASs are persistent in the environment, bioaccumulate, and persist in organisms and the human body for extended periods of time, so they can interfere with cellular receptors and promote chronic toxicity and cancer.
At UPO, we develop highly sensitive analytical methods using a state-of-the-art analytical technique based on high-performance liquid chromatography (HPLC) combined with a high-resolution mass-accuracy (HRMA) mass spectrometer, the Orbitrap Exploris 120 (Thermo Scientifics) (figure below). PFASs generally occur at trace levels and their detection requires highly sensitive and reliable analytical methods. In addition, many materials used in sampling and analysis may contain PFASs due to their widespread use and persistence. To avoid cross-contamination and achieve the level of accuracy and precision required for defensible results, we take a conservative approach and apply the highest level of rigor to all aspects of sampling elements (e.g., sample container type, preservation, holding time) and analytical elements (e.g., sample preparation, consumables such as filters, solvents, and vials). In addition, we use standards with isotopically labeled analogs to improve the quality and reliability of results.
Our ambition is to significantly improve currently available methods for the detection and quantification of PFAS in drinking water or in more complex matrices, including surface waters, solids, human blood and animal tissues, and thus providing robust and sensitive data on the largest possible number of PFAS congeners. In addition to developing methods to quantify target PFAS, HRMS can also be used to identify unknown PFAS in a sample using non-target analysis (NTA) methods. However, unambiguous structural identification and quantification of tentatively identified PFASs requires the use of analytical standards. In general, accurate identification of PFASs using non-target HRMS is a time-consuming and resource-intensive process. The team at UPO has taken on the challenge of developing an NTA workflow using HRMS and applying their expertise in analytical chemistry and chemometrics to deal with the rather complex data and improve the interpretation of results.
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