Comparison of solid phase microextraction coatings for headspace extraction of volatile perfluoroalkyl substances...

Volatile and semi-volatile per- and polyfluoroalkyl substances (PFAS) represent an important, yet analytically challenging subset of emerging contaminants. The low atmospheric abundance, high vapor pressures, and susceptibility of these analytes to loss during sample handling necessitate preconcentration strategies capable of capturing these chemically diverse species at trace levels. Solid phase microextraction (SPME) is a solvent-free, equilibrium-based approach well-suited to these challenges, facilitating effective preconcentration while minimizing analyte loss. A key advantage of SPME is the tunability of the sorbent phase chemistry, which enhances extraction efficiency across analytes with diverse physicochemical properties.

In this work, a hydrophilic-lipophilic balance/polydimethylsiloxane (HLB/PDMS) SPME Arrow sorbent phase was compared with a divinylbenzene/carbon-wide range/polydimethylsiloxane (DVB/C-WR/PDMS) SPME Arrow across 15 volatile and semi-volatile PFAS spanning 5 structural classes. The HLB/PDMS phase exhibited higher responses across the suite of PFAS, with 706% and 284% greater peak areas for 4:2 FTOH and 6:2 FTOH, respectively, compared to DVB/C-WR/PDMS. Chromatographic performance was further assessed using both one-dimensional and comprehensive two-dimensional gas chromatography-mass spectrometry (GC-MS and GC×GC-MS). For the most volatile analytes, improvements in limits of quantification (LOQs) were observed; the LOQ for F-Hexene decreased from 0.05 μg L^-1 using 1D GC-MS to 0.005 μg L^-1 with GC×GC-MS.

This study demonstrates, for the first time, the successful extraction and quantification of volatile PFAS using an HLB/PDMS SPME Arrow. The developed SPME-GC×GC-MS workflow provides a sensitive, solvent-free, and broadly applicable method for trace-level volatile PFAS detection in aqueous, gaseous, and complex solid matrices. These advances establish a versatile platform for comprehensive monitoring of volatile PFAS.