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Just like gum on the bottom of a shoe, the existence of per- and poly-fluorinated alkyl substances (PFAS) in our environment is a sticky one. If you’re in the field of environmental testing, then you’re all too familiar with the threat these substances have on public health. While we have learned a lot about them over the years, there is still much more to understand. With the right detection methods, we can gather the information we need to empower us to make informed decisions on reducing the risks they impose.

Putting the spotlight on PFAS

PFAS are unique, man-made chemicals used extensively in consumer and industrial products. Over the years, we have come to learn that the physicochemical properties which make them useful and long-lasting, are the same properties that make them persistent in the environment.

Because of the interconnected nature of our world, the concern about PFAS and its harmful effects goes far beyond the environment. PFAS accumulate in the body, potentially resulting in chronic health effects. Additionally, PFAS compounds typically exist at low concentrations, requiring low method detection limits, which affects our ability to identify and monitor them.

Now more than ever we have an urgent need for sensitive and highly selective analytical testing methods to get information that can help us monitor, regulate and limit their long-term effects.

Turning to high-resolution accurate mass spectrometry (HRMS)

If you’re a PFAS researcher, you are aware that PFAS analysis is challenging. The diverse nature of these compounds makes testing extremely complex. Some laboratories might lack capabilities like sensitivity and mass accuracy, which are necessary for achieving low detection limits, precise identification and compound differentiation.

To help overcome these barriers, more laboratories are turning to high-resolution mass spectrometry (HRMS). Compared to traditional triple quadrupole mass spectrometry, HRMS has the ability to discover new PFAS compounds. As this technology improves and more researchers adopt HRMS, it is likely that more novel PFAS compounds will be discovered. For all the legacy PFAS that exist, there are many more to discover, which leaves us with one question – how do we know what to look for if we don’t know it exists?

Ensuring that no PFAS compounds are overlooked

With the large number of known PFAS compounds in existence today and the growing number of newly discovered PFAS, the right analytical techniques play a pivotal role in answering our question.

While a targeted analysis can be used to quantify known PFAS compounds, we are learning that these methods don’t always capture all the PFAS compounds in a sample. Regulated methods only monitor ~20-40 PFAS, which represents only a tiny fraction of the estimated compounds that exist.

Suspect screening and non-targeted analysis offer a more comprehensive approach. Their broad detection capabilities can identify a wider range of PFAS compounds, including those that we don’t know or only suspect exist. With these approaches, we can increase our coverage of PFAS compounds.

High confidence, even higher reliability

While it’s exciting to see the scientific advancements made with HRMS, it has also presented an additional challenge. Because there are so many undiscovered PFAS compounds, we lack the analytical standards that are needed to confirm what we see. Until recently, it has been difficult to be confident about what we see in our data.

In response to a need for a standardized approach to confirm the identities of small contaminant molecules using HRMS, Emma Schymanksi and her colleagues developed a scale. Emma is a widely recognized expert in environmental chemistry and her contributions have greatly shaped how environmental contaminants such as PFAS are studied, especially through non-targeted techniques and HRMS. This scale has since been adapted to other testing areas and has come in handy in our ability to communicate confidence in PFAS.

When we communicate confidence in our data, we show confidence in the results. This ensures the data can be used appropriately for compliance decisions, reduce the risk of misuse and enables well-informed decision-making.

Moving toward a healthier, safer future

As the understanding of PFAS continues to evolve, so does the need for more comprehensive testing strategies. At SCIEX, we work closely with end-users and researchers to develop tailored testing methods and innovative instruments that elevate their research. Our ZenoTOF 7600 system, equipped with a Zeno trap, boosts MS/MS sensitivity to enable more confident identifications even at low concentrations. Additionally, electron-activated dissociation (EAD) allows us to provide unique fragments that can be used to elucidate certain PFAS compounds that produce few diagnostic fragment ions using traditional collision-induced dissociation (CID). We’ve come a long way in our journey of PFAS identification and the unique tools we use to detect them – and we aren’t done yet!

If you’d like to expand your expertise in using accurate mass spectrometry technology to tackle current and future challenges in PFAS testing, check out our Accurate mass 101 webinar series.