The Consult

In a recent episode of the PFAS Pulse Podcast, hosts Tom Simmons and Matt Wallace were joined by Lindsay Boone, MSc., of Pace® Analytical Services, for a deep dive into per- and polyfluoroalkyl substance (PFAS) testing methodologies. From sample contamination to the future of PFAS air sampling, Lindsay offered insight grounded in real data and lab experience.Here are some top takeaways:

PFAS and cross contamination 

Are we being too cautious—or just doing it right?
When PFAS testing first emerged, the concern around cross contamination was intense—no deodorant, no sunscreen, no showers before sampling. “PFAS is everywhere, so we were hyper-aware,” recalls Lindsay Boone.

But to validate whether that concern was warranted, the team at Pace® took a data-driven approach. They pulled over 14,000 data points from EPA Methods 533 and 537.1 and analyzed the field blanks—secondary samples collected in the field to test for contamination introduced during the sampling process.

“We looked at whether any hits showed up at or above the 2 parts per trillion reporting limit,”Lindsay says. The result? Less than 1% of field blanks showed PFAS hits, suggesting the sampling protocols are working. “Maybe we were over-cautious—or maybe we’ve just gotten really good at this.” Lindsay also encourages clients to always check quality assurance/quality control (QA/QC) data, especially method blanks, which help distinguish between field and lab contamination.

“And remember,” she adds, “field blanks at times can cost the same as a regular sample. Depending on your budget and the sample type, sometimes it’s better to run a duplicate instead.”

Air sampling for PFAS is still in the early stages

Air is one of the final frontiers of PFAS monitoring. While PFAS air regulations are slowly emerging, testing methods are still limited—and largely focused on PFAS manufacturers.

“We haven’t seen a lot of regulations in air. There are certain facilities that do have PFAS written into their air permits. We’ve got a couple of methods that are utilized for air. The first one was OTM 45 which tests for a pretty standard list of PFAS utilizing a sampling train. It has been around for sometime now. You essentially catch the PFAS on a resin, and labs extract it. We also have OTM 50 that analyzes for more volatile fluorinated compounds. Those two methods will be used together. I’ve seen utilized in incinerator situations and leachate evaporators. But where is it going from a regulatory standpoint? We just don’t know yet.

The bottom line: we have methods, but broad regulatory momentum hasn’t fully landed in the air space yet. Watch this one — it’s evolving fast.

EPA Method 1633: Standardization, strengths—and some solid challenges

When it comes to PFAS testing for non-potable water and soil matrices, EPA Method 1633 has quickly become the go-to for compliance, especially in contexts like NPDES discharge permits or groundwater monitoring near landfills. “The beauty of EPA Method 1633 is that it standardizes nonpotable testing—labs no longer need to guess which PFAS compounds to target,” says Lindsay Boone. The method specifies 40 compounds with the ability to expand that list and works across a range of matrices from groundwater to AFFF.

“We’re finally speaking the same language when it comes to non-potable testing,” Lindsay says.

It also delivers impressively low reporting limits, in some cases reaching levels similar to drinking water methods. The drawbacks? It’s more expensive and has a longer turnaround time due to its complexity. “It uses a solid phase extraction cartridge that can get clogged by high solids,” Lindsay explains. To address this, labs like Pace® have developed modified workflows—such as centrifugation—to reduce solids and preserve sample integrity, all while keeping those crucial detection limits as low as possible.

Want to learn more?

For a more in-depth exploration of these topics and more, listen to the full episode of the PFAS Pulse Podcast featuring Lindsay Boone.