When a UK contamination site was suspected of extensive pollution with per- and polyfluoroalkyl substances (PFAS), environmental forensics expert Dave Megson knew standard testing wouldn’t be enough. Traditional methods focus on known PFAS compounds from regulatory target lists. Megson’s goal was clear—uncover the full spectrum of PFAS at the site and illustrate why non-targeted analysis is essential to complement traditional testing methods.
For support, Megson partnered with Agilent and applications engineer Jonny Spencer, an expert in liquid chromatography-mass spectrometry (LC/MS). Spencer saw the project as an opportunity to leverage Agilent’s 6546 LC/Q-TOF, which offers the sensitivity, dynamic range, resolution, and mass accuracy needed to broaden the scope of PFAS detection.
Challenges in Non-Targeted PFAS Analysis
Untargeted PFAS analysis demanded that Megson and Spencer sift through complex datasets to uncover both known and unreported compounds present at the site. The global catalog of PFAS, nearing 10,000 and growing, highlighted the scale of the problem and the critical need for precise, high-quality data to confidently identify contaminants.
A major obstacle was the lack of commercial analytical standards. While millions of PFAS compounds are suspected to exist, very few have standards available, making it difficult to confirm the identity of suspected PFAS in non-targeted samples.
Additionally, identifying unknown compounds involved acquiring a large number of high-quality MS/MS spectra. This process became even more difficult when samples contained a mix of chemical components that interfered with the data.
Innovative Solutions for PFAS Detection
To overcome these barriers, the team relied on Agilent’s 6546 Q-TOF LC/MS system paired with FluoroMatch software. Best known for small molecule analysis, this combination offered a suite of powerful tools tailored for non-targeted PFAS detection.
- Exact mass matching enabled precise molecular identification, distinguishing PFAS from other compounds in complex datasets.
- Fragment screening validated suspected PFAS by confirming their structural integrity.
- Homologous series detection identified repeating molecular patterns unique to PFAS, revealing related compounds that might otherwise have gone undetected.
Agilent’s MassHunter Qualitative Analysis software also provides features, such as the Molecular Formula Generator, that are effective at identifying PFAS, notes Spencer.
An iterative MS/MS workflow on Agilent LC/QTOFs enhanced the acquisition of high-quality spectra by enabling repeat injections. Each injection captured unique MS/MS signals, expanding coverage and improving the detection of a broader range of PFAS.
Uncovering Hidden Contaminants
Spencer and Megson’s non-targeted workflow uncovered the full extent of PFAS contamination at the site. The findings were striking—just 17% of identified compounds appeared on the UK’s regulatory target list, leaving 83% unregulated.
Among the unregulated compounds, EEA-NH4 stood out as the most abundant. This compound, an ammonium salt of ethyl ether carboxylic acid, is used in certain industrial processes and may act as a precursor for other PFAS compounds. "Intriguingly, we also identified several PFAS that have not been previously reported which seemed to be related to the presence of EEA-NH4," Spencer remarks.
A Broader Role for Non-Targeted Analysis
The chemical diversity of PFAS compounds demands workflows that extend beyond a single approach. “Some PFAS compounds respond better to GC/MS,” explains Spencer. “Using multiple complementary techniques can significantly increase a lab’s coverage of total PFAS components.”
Spencer highlights the importance of high-resolution accurate mass spectrometry and MS/MS capabilities for non-targeted analysis. He notes that instruments such as Agilent’s Revident Q-TOF, which expands on the 6546 Q-TOF’s capabilities, provide the precision and reliability needed for comprehensive workflows.
Shaping the Future of PFAS Monitoring
“These findings underscore the limitations of relying solely on targeted analysis, which typically focuses on a small number of known PFAS compounds,” explains Spencer. He suggests this approach could guide regulatory bodies toward broader PFAS monitoring and encourage more rigorous industry testing.
Megson and Spencer’s research didn’t stay confined to the lab. Their co-authored paper and conference presentation engaged environmental experts and policymakers, demonstrating how advanced tools and collaboration can shape better monitoring practices and policies to protect public health and ecosystems.
Meet the Expert
Jonathan Spencer
Jonny Spencer began his career as a confirmatory analyst in an anti-doping and forensic toxicology lab. Over the past eight years, he has worked as an LC/MS Applications Specialist at Agilent, specializing in small molecule analysis using LC/TQ and LC/QTOF technologies. His expertise spans various fields, including environmental analysis, forensic toxicology, and food safety.
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