PFAS in air: Validating ASTM D8591 for the measurement of airborne fluorotelomer alcohols

Fluorotelomer alcohols (FTOHs) are volatile and semi-volatile PFAS used in the manufacture of surfactants and consumer products. As FTOHs can degrade into persistent and regulated perfluorinated carboxylic acids, there is increasing demand for reliable, standardised methods for their determination in air samples.

ASTM D8591-24 defines a TD–GC–MS/MS workflow for trace-level measurement of FTOHs collected on sorbent tubes. In this application note, we validate the use of a Markes thermal desorption system for compliance with the method, assessing background levels, chromatography, linearity, detection limits and data-quality performance. The work also contributes to the ASTM interlaboratory validation study that supported publication of the standard.

Analytical performance highlights

• Compliance with ASTM D8591-24
  All calibration, recovery and quality-control criteria specified by the method are met.

• PFAS-free TD flow path
  Blank tube analyses show no measurable contribution from the thermal desorption system, supporting confident trace-level quantitation of FTOHs.

• Chromatographic performance and linearity
  Well-resolved peaks and low relative response factor RSDs are achieved across the calibration range, meeting ASTM acceptance criteria.

• Low limits of detection
  Detection limits of 14–35 pg are achieved for the four target FTOHs, demonstrating suitability for trace-level air analysis.

• Avoidance of solvent-derived PFAS background
  Thermal desorption removes the need for solvent extraction, eliminating a known source of PFAS contamination and analytical variability.

• Automation of complex QC sequences
  Automated tube handling supports the demanding calibration and quality-control workflows required by ASTM D8591-24, improving throughput for extended sequences.

Application areas

• PFAS emissions testing

• Environmental and occupational air monitoring

• Materials and product emissions assessment

• Standards-driven and regulatory laboratories

This study demonstrates that TD–GC–MS/MS provides a robust and contamination-aware approach for FTOH analysis, supporting reliable implementation of ASTM D8591-24 in routine laboratory workflows.