Effective workflow development is key in any analytical laboratory. Using the right tools and technologies ensures that scientists are able to achieve suitably accurate and repeatable results while meeting throughput goals and other objectives. As the analysis of per- and polyfluoroalkyl substances (PFAS) continues to be an area of focus in analytical laboratories across the globe—with no sign of going away anytime soon—there is an increasingly intense spotlight on the workflows used for this type of testing.
At the workflow development stage, laboratory personnel must consider each component, from consumables to instruments to software. As with other types of analysis, a broad range of factors are at play, including sensitivity, contamination potential, and sustainability, to name a few.
Dr. Tarun Anumol, Global Environmental Market Director at Agilent Technologies, has vast experience working on various components of PFAS workflow development. Through this in-depth interview, he elucidates the nuances and challenges of PFAS analysis, emphasizing its importance and the technological strides made to support scientists in their pursuits.
Could you describe how PFAS analysis has changed over time and the importance of some of the different testing methods?
PFAS testing has changed in quite a few ways. One of the ways to look at it is through the lens of the lab analysts and the major challenges they are facing. One of the issues is that PFAS have become so ubiquitous, and we're realizing this is not just limited to an environmental problem, with PFAS being present only in water, soil, and air. We're finding PFAS in many consumer products and materials, for example, even in medical devices. That said, another challenge with PFAS is the scope. Depending on the definition of PFAS, we expect that anywhere from around 5,000 to a million PFAS have been produced, and many of them have been used in commerce. We are currently only looking at about one or two percent of those from a regulatory perspective. As we conduct more research, we continuously add new compounds to test for, broadening the analytical scope, which is a big challenge for analytical chemists in the lab. The third major challenge around PFAS testing, and where much of the evolution is happening, relates to how we address the background contamination. What's interesting from an environmental perspective is the levels that we're looking at for PFAS are about 1,000 to 10,000 times lower than previously regulated contaminants that we've analyzed, such as pesticides and semi-volatile organic compounds. As such, the sensitivity required is a lot higher. But that also means you need to have much cleaner backgrounds in your lab and ensure your analysis is robust and reliable in those low concentrations. The fourth challenge, and again where PFAS analysis is evolving, is continually changing regulations. New analytical methods are under development for various matrices in different countries and regions. These come with new regulations, which can also mean different accreditations and audits. So, PFAS analysis is constantly evolving considering all these factors, and labs have to be aware and on top of them to be at the forefront of producing the highest quality PFAS data.
What is the importance of having streamlined and efficient workflows for PFAS detection?
What is interesting with the PFAS workflow is you really need to consider the entire process, including sample collection, sample preparation, extraction, instrumental analysis, data processing, and data reporting, to be successful. Unlike for many other analytes, the instrumental analysis for PFAS is not the most difficult or challenging part. These compounds love to be ionized, especially on LCMS instruments. The bigger challenges for the lab are around making sure you're not introducing PFAS as background, because of how low we are looking to measure them and the latent presence of PFAS everywhere. PFAS are often present in common lab materials, such as laboratory glassware or tools, sample preparation equipment, and consumables, and they’re even present in lab surroundings. Thankfully, there are specific products and tools that are QC'd for PFAS. In response to these challenges, Agilent and other vendors have characterized their LCMS systems to ensure they are not introducing fluoropolymers or other PFAS. Considering the entire workflow is more critical in PFAS than in many other analyses, and you really need to limit the potential for contamination at each stage.
How large of an issue are consumables in PFAS workflows?
PFAS analysis requires very high sensitivity, which typically means you need more sample preparation, more cleanup, and more extraction or concentration. That would typically lead us to think we need more tools. But many of our traditional lab consumables come into contact with fluoropolymers, which can be a source of PFAS contaminants. Analysts need to watch out for some of the most basic items normally used in labs. For example, vial caps often have PTFE, a fluoropolymer that can add PFAS contamination into your sample. In other cases, PFAS may not be involved in the manufacturing process, but they can appear as contaminants in the raw materials. This means you can have varying backgrounds from batch to batch of consumables. To address this, Agilent has produced a line of PFAS products including vials, caps, filters, and SPE cartridges that go through QC to check for the presence of any PFAS. But while much of the onus is on consumables manufacturers, the end user also has a responsibility to follow best practices, including performing QA and QC, and following SOPs that outline steps such as checking and recording batch and lot numbers. Most laboratories do this, but the importance has been heightened with PFAS because of the increased contamination potential that we've seen. We're also measuring these compounds at much lower levels than some of the other regulated analytes we look at, further increasing the potential for contamination.
You mentioned the issue of background PFAS. Can you discuss some of the other contributors to consider?
PFAS are found in so many products and in our natural environment. For example, we used to spray products that contain PFAS on carpets to prevent liquids seeping in, and some of these carpets might be found within laboratories. Another example is air conditioning filters. Many of these use fluoropolymer filters, such as PTFE filters, which can potentially cause PFAS contamination. Many cosmetics can also contain trace levels of PFAS. Your clothes might even be coated with fluorinated compounds—for example, the water-resistant coating on raincoats often contains PFAS. While it's not impossible to limit background PFAS, these considerations highlight the importance of good laboratory practice and having robust QA and QC, both on raw materials and throughout the analytical workflow.
When it comes to improving workflow efficiency, how can software help to improve the data review process?
The secret that's not so secret is that most analytical chemists spend about 60 to 70% of their time using software to review, process, and evaluate data. The hardware has come so far that you no longer have to spend hours manually tuning your instruments, and maintenance is significantly lower and simpler. There are three critical factors to consider when selecting software for PFAS workflows. One is it needs to be intuitive so that it doesn't require a mass spectrometry expert and a novice can use it effectively. It's also important to reduce the amount of cross training and expertise required. Ideally, software across different instrumentation (such as GC, GC/MS, ICP/MS) should be similar so that personnel can easily operate multiple instruments. Finally, chemists want to minimize the amount of time they spend on manual evaluation of data, such as re-evaluation of peaks and manual integration. In one sample of PFAS, you're typically analyzing somewhere between 20 and 60 different components. In a batch of 100 samples, that's 6,000 individual peaks that a lab chemist might have to look at. Ideally, they shouldn't have to review peaks at all. This is really where the benefit of the new software comes in, including making use of certain tools like AI and machine learning to learn how peak integration is performed. There are also special functions such as "review by exception," where the software only flags chromatograms that are potential outliers based on certain criteria input by the user. These tools reduce manual review time and significantly increase lab throughput.
How does software impact other areas of the workflow?
Aside from the back-end data processing, we also need to consider the front-end data acquisition software. One example that resonates with most chemists is starting a run at the end of the day, going home, and coming back the next day to find out only a few samples ran because of an issue with the instrument. Or perhaps the whole batch ran, but one of the samples was a "hot sample" that contained a very high concentration of PFAS and contaminated the next few samples, so now you need to run everything again. To address these issues, some software providers are incorporating automated feedback loops at the data acquisition stage. When the software determines the concentration or response in a particular sample is above the response of the highest calibration curve, it can automatically pause the worklist and notify the user. Or it can even run blanks until the concentration comes down. Software can address other issues, too. For example, if solvents are running low, instead of continuing to run samples without solvent, the software can recognize the problem, pause the worklist, and notify the user. These tools help to reduce the number of re-runs, increasing efficiency. They also help guide novices who may not consider certain factors. One more area to acknowledge is the environmental sustainability component. Analysts, particularly those working in environmental laboratories, want to minimize sample waste, reduce the amount of organic solvent requiring disposal, and avoid using power unnecessarily. A more efficient workflow, assisted by modern software, can help with all of these factors.
Do you have any final thoughts to share on the topic of PFAS analysis?
My favorite saying within PFAS analysis is that you can't manage what you can't measure. We really need to find the right strategies to measure PFAS in the environment. Only once we've determined the levels, occurrence, and prevalence can we decide on the appropriate remediation strategies. While no one wants to get into environmental situations such as this, particularly where pervasive contaminants are involved, it's positive that the issue has come to light and authorities are taking mitigating steps. This is an important time in analytical chemistry, and we'll likely be conducting PFAS analysis testing for the next several decades at least.
Aimee Cichocki is the managing editor for Separation Science. She can be reached at acichocki@sepscience.com.
Tarun Anumol is currently the Director for the Global Environment Markets at Agilent Technologies where he is responsible for developing the strategy for environmental testing. He previously served in marketing manager roles for the food and environmental markets. Prior, Tarun was an LC-MS applications scientist at Agilent, focused on developing analytical methods for trace contaminants like PFAS, hormones, drugs and algal toxins on LC-MS/MS and LC-Q/TOF in the food and environmental matrices. Tarun has a strong history of working in the environmental testing industry, with a background in technical and applied science, with over 30 peer-reviewed journal publications in this area. He currently serves on the executive committee of the Environmental Sciences Section for the American Council of Independent Laboratories (ACIL), the chair of the Industrial Outreach Committee for the American Chemical Society (ACS) and on the Steering committee for the National Environmental Monitoring Conference (NEMC). Prior to joining Agilent, Tarun graduated with a Ph.D. in Chemical & Environmental Engineering from the University of Arizona working on developing analytical methods and strategies for measuring and attenuating emerging contaminants like PFAS, pharmaceuticals and disinfection byproducts in relation to water reuse. Tarun also holds an MS in Civil & Environmental Engineering from Carnegie Mellon University.
This article is featured in our October publication, 'PFAS: Unraveling the Analytical Challenges.' From cutting-edge analytical methods to the unexpected avenues of PFAS exposure in everyday items, explore the multifaceted challenges and solutions surrounding these pervasive contaminants.
