SP 04 - Identification and Quantification of Fluorinated Organic Compounds (PFAs) in Air a New Analytical Challenge
SP 04 - Identification and Quantification of Fluorinated Organic Compounds (PFAs) in Air a New Analytical Challenge
Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic compounds widely used in consumer and industrial products for their non-stick, water-repellent, and stain-resistant properties. However, their persistence, potential toxicity, and bioaccumulative nature have raised significant public health and regulatory concerns. Indoor environments, where people spend over 90% of their time, are now recognized as important reservoirs for PFAS due to off-gassing and volatilization from treated materials. Measuring these substances in indoor air is crucial to understanding exposure risks and informing mitigation strategies. This study presents the development and application of a sensitive and robust analytical method combining thermal desorption (TD), gas chromatography (GC&GCXGC), and triple quadrupole mass spectrometry (MS/MS) for the targeted measurement of 19 PFAS compounds in indoor air. The method employs Markes’ TD100-xr™ thermal desorber, which features advanced technologies such as electrically-cooled focusing traps, backflushing for improved analyte recovery, and sample re-collection capabilities for validation and reanalysis. Targeted compounds span four functional groups: perfluoroalkyl carboxylic acids (PFCAs), fluorotelomer alcohols (FTOHs), fluorotelomer carboxylic acids (FTCAs), and sulfonamides (FOSAs). The method achieved excellent chromatographic separation and high linearity (R² > 0.99 for all compounds), with detection limits down to 1 pg for Me-FOSA and an average method detection limit of 16 pg per compound. Calibration covered a broad concentration range, enabling quantification of PFAS at both low and high levels, which is particularly useful given the elevated concentrations typically observed indoors compared to ambient air. Real-world sampling campaigns were conducted in both workplace and residential environments. Workplace air samples showed total PFAS concentrations ranging from 38.35 to 156.95 ng/m³, with the highest levels detected in a corridor area. In contrast, residential air samples from a home undergoing renovation had significantly lower total PFAS levels (11.15 ng/m³), though fluorotelomer alcohols dominated the compound profile. These findings emphasize the diversity of PFAS sources indoors and the variability of contamination depending on material use and building activities. To investigate material-specific emissions, a child’s waterproof coat was analyzed using the Micro-Chamber/Thermal Extractor™. This approach enabled the quantification of PFAS released from the material at ambient temperature. The dominant compound emitted was 8:2 FTOH, with a concentration of 3.9 ng/g and an emission rate of 0.131 ng/g/min. Such data are essential for developing emission inventories and for potential regulatory limits on PFAS-containing consumer products. Overall, this work demonstrates that the TD–GC–MS/MS method is a highly effective and scalable approach for PFAS analysis in indoor environments. It offers sufficient sensitivity, precision, and flexibility for regulatory and research applications.
Keywords: PFAS in air, thermal desorption, GCXGC-MS, GC-MS/MS