Volatile PFAS: Implications for Industry and the Role of TD-GC-MS/MS

Volatile and neutral PFAS species represent a distinct analytical and regulatory challenge compared with the more widely discussed ionic PFAS measured by LC-MS/MS. Two GC-based methods now define the industrial analytical landscape for volatile PFAS: ASTM D8591-24 and U.S. EPA OTM-50. While both rely on thermal desorption coupled to gas chromatography–mass spectrometry (TD-GC-MS or TD-GC-MS/MS), they serve fundamentally different regulatory and industrial objectives.

Understanding this distinction is essential for laboratories, manufacturers, and waste treatment operators implementing either method.

Thermo Fisher Scientific: Volatile PFAS: Implications for Industry and the Role of TD-GC-MS/MS

ASTM D8591-24: emissions from materials and products

ASTM D8591-24 is a standardized test method for the determination of fluorotelomer alcohols (FTOHs) in air samples collected on thermal desorption tubes. It was validated for air samples collected from environmental test chambers and is particularly relevant to materials emissions testing.

The method addresses a critical analytical gap: 

FTOHs and related neutral PFAS species are not reliably measured by LC-MS methods due to chromatographic and ionization limitations, while GC-based methods are appropriate for volatile fluorinated compounds and neutral PFAS species, including FTOHs.

From an industrial perspective, ASTM D8591-24 has implications in three areas:

1. Product stewardship and compliance. Manufacturers of textiles, packaging, coatings, and consumer goods increasingly require defensible emission data. The Application Note: Analysis of PFAS in indoor air using thermal desorption coupled to gas chromatography – mass spectrometry (TD-GC-MS/MS) on indoor air testing demonstrates that TD-GC-MS/MS can detect PFAS species at low ng/m³ levels, with average method detection limits around 780 pg/m³ for a 20 L air sample. Such sensitivity is necessary when evaluating exposure in workplaces or residential settings.
2. Chamber testing and emission rate determination. The Micro-Chamber/Thermal Extractor (µ-CTE) enables controlled emission studies of materials without extensive preparation. As shown in the application note, fluorotelomer alcohol 8:2 (FOET) was the dominant emission, with a calculated emission rate of 0.131 ng/g/min.  Emission rates rather than bulk concentration increasingly form the basis of regulatory thresholds.
3. Laboratory workflow and reproducibility. The TD100-xr coupled with TRACE 1610 GC and TSQ 9610 triple quadrupole MS provides automated internal standard addition, dry purge, and cryogen-free focusing. The integration with Chromeleon CDS supports controlled method setup and compliant data handling.

ASTM D8591-24 standard is therefore positioned at the interface of product emissions, occupational exposure, and indoor air quality.

EPA OTM-50: Verification of PFAS Destruction

EPA Other Test Method 50 (OTM-50) occupies a different regulatory space. It is intended for sampling and analysis of volatile fluorinated compounds (VFCs) emitted from stationary sources, particularly those associated with PFAS destruction processes.

The analytical objective is not product emissions but verification of mineralization efficiency. Incomplete destruction of PFAS can produce volatile by-products such as carbon tetrafluoride (CF₄), a persistent and potent greenhouse gas. OTM-50 therefore serves as a tool for assessing process performance in chemical manufacturing and waste management facilities.

The implementation of OTM-50 introduces distinct analytical challenges:

• Ultra-volatile targets. CF₄ is difficult to trap, often requiring specialized trapping strategies
• High CO₂ backgrounds. CO₂ can co-trap with analytes and bias results; OTM-50 includes a bias check with ±30% acceptance criteria
• High humidity. Emission streams may approach 100% relative humidity, requiring effective water management
• Trace-level detection with robustness. Achieving ppt-level detection while maintaining stability and calibration integrity is non-trivial

Thermo Scientific solutions for OTM-50 combine Markes UNITY-xr cryogen-free preconcentration, dedicated focusing traps for volatile fluorocarbons, automated internal standard addition, and either ISQ 7610 single quadrupole GC-MS or TSQ 9610 triple quadrupole GC-MS/MS detection. For facilities seeking enhanced selectivity and lower limits of quantitation in complex emission matrices, GC-MS/MS provides additional confirmation capability beyond single quadrupole operation.

OTM-50 is currently an “Other Test Method,” but its role in demonstrating destruction efficiency suggests increasing regulatory significance. Facilities adopting it are not simply measuring emissions; they are generating defensible evidence of process performance.

Complementary but distinct

Although ASTM D8591-24 and EPA OTM-50 both rely on TD-GC-MS(/MS), their scope differs fundamentally:

• ASTM D8591-24: Chamber or ambient air sampling on sorbent tubes; focuses on FTOHs and related neutral PFAS; applied to materials emissions and indoor air.
• EPA OTM-50: Canister-based sampling of stationary source emissions; focuses on volatile fluorinated compounds from destruction processes; applied to industrial compliance and process verification

In practical terms, ASTM D8591-24 addresses the question: What is emitted from products and materials?
OTM-50 addresses: What remains after PFAS destruction?

For laboratories and industrial operators, the implication is clear. No single analytical approach covers all PFAS species or all regulatory questions. A TD-GC-MS/MS platform configured appropriately can support both methods, but the sampling strategy, validation framework, and regulatory context differ.

As volatile PFAS monitoring expands, from product stewardship to destruction verification, the analytical distinction between these two methods will remain central to effective implementation.

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Daniela Cavagnino, M.S.

Daniela Cavagnino is a Product Marketing Manager who built a career at Thermo Fisher Scientific, transitioning from GC R&D scientist to product and marketing leadership with 20+ years in GC/GCMS.