Simultaneous analysis of neutral and ionizable per- and polyfluoroalkyl substances in air

A new method is preliminarily validated for the simultaneous analysis of ionic and neutral per- and polyfluomalkyl substances (PFASs) in both particulate and gaseous phases in air using a nanosampler-20 air sampler (NS20) composed of quartz fiber filters (QFFs), polyurethane foam (PUF) and artificial activated charcoal (GAIAC (TM)). Perfluoroalkane sulfonamido ethanols (FOSEs) mainly remained in PUF, whereas the other neutral analytes were mainly found in GAIAC. Satisfactory recoveries were obtained for FOSEs, fluorotelomer alcohols (FTOHs), fluomtelomer iodides (FTIs), ranging fron 70%-120%, moderate recoveries were achieved for perfluorinated iodine alkanes (FIAs) and diiodofluoroalkanes (FDIAs), ranging from 50%-70%, while poor recoveries were found for perfluoroalkane sulfonamides (FOSAs). Breakthrough experiments revealed that almost all the target analytes were well trapped in GAIAC (TM), including the very volatile 4:2 FTOH. Applying to real sampling, our results showed that 6:2 and 8:2 FTOH were the most abundant species, with levels detected at 190 pg/m(3) and 160 pg/m(3). To the best of our knowledge, FDIAs were detected in ambient air for the first time at an average level of 8.3 pg/m(3). Overall, the profiles observed from the real air samples reflected current industrial transition from longer chain to shorter chain in PFAS production. Our results revealed that the current method is promising for a more comprehensive understanding on the fates of PFASs in air.

Automated summary

A new method using a nanosampler-20 air sampler was validated for the simultaneous analysis of ionic and neutral PFASs in air, showing different distribution patterns of PFASs in various materials and different recovery rates for different compounds. In real air samples, 6:2 and 8:2 FTOH were identified as the most abundant species, while FDIAs were detected in ambient air for the first time. The study indicates a shift in PFAS production from longer chain to shorter chain compounds in current industrial practices.