A Breakthrough in PFAS Monitoring: Speed and Portability
Per- and polyfluoroalkyl substances (PFAS) are a class of “forever chemicals” that resist degradation and accumulate in water, soil, and people. Researchers from the University of Chicago’s Pritzker School of Molecular Engineering (UChicago PME) and Argonne National Laboratory have developed a portable, handheld sensor capable of detecting miniscule PFAS levels in water within minutes. This technology, described in Nature Water, promises faster, on-site testing for PFOS and PFOA, two PFAS of particular concern to health and regulation.
How the Handheld PFAS Sensor Works
At the heart of the device is a silicon chip whose surface conductivity changes when a PFAS molecule binds to a specially chosen probe. The team uses a suite of molecular probes designed to recognize specific PFAS chemicals. When PFAS binds, the device records a change in electrical conductivity that correlates with concentration. The approach blends state-of-the-art materials science with artificial intelligence to achieve high specificity even in the presence of other common tap-water contaminants.
Machine learning plays a crucial role in probe design. By sifting through thousands of potential probes, the algorithm predicts which ones will most effectively bind to a particular PFAS, such as PFOS, while discriminating against non-target molecules. This automated probe selection accelerates development and helps tailor sensors for individual PFAS.
Validation and Real-World Relevance
The team validated the portable sensor against EPA-approved liquid chromatography/tandem mass spectrometry (LC-MS/MS) methods, confirming that the handheld readings align with established laboratory results. Crucially, the device demonstrated accurate readings for PFOA and PFOS at extremely low concentrations—the parts-per-quadrillion (ppq) range—well beyond typical field tests. The system also maintained performance over multiple detection and rinse cycles, a key attribute for ongoing monitoring in real-world settings.
Why This Matters for Public Health and Policy
PFAS contamination poses a persistent challenge due to their persistence, ubiquity, and potential health effects, which have included cancers, thyroid issues, and immune system impacts. The EPA’s proposed limits for PFOS and PFOA underscore the need for sensitive, accessible testing methods. A handheld PFAS detector could empower water utilities, regulators, and even households to quickly assess drinking water quality, identify contamination hot spots, and guide remediation decisions without waiting weeks for lab results.
Lead investigator Junhong Chen notes that current lab-based testing can be slow and equipment-intensive. By contrast, the new sensor offers rapid, on-site measurements, enabling more timely responses to PFAS risk. As the team expands the probe library to cover additional PFAS chemicals, the technology could scale to monitor a broader range of contaminants, antibiotics, and even pathogens in water systems.
Looking Ahead: From Research to Everyday Use
The researchers envision a future where consumers, utilities, and environmental agencies use handheld devices to test water quality in real time. Ongoing work will focus on expanding probe libraries, improving multi-analyte sensing, and ensuring robustness across diverse water matrices. With continued validation and potential regulatory acceptance, these sensors could become a routine tool for protecting drinking water and public health.
Expert Perspectives
Advocates of rapid PFAS testing emphasize the need for accessible tools that complement laboratory methods. Andrew Ferguson, a professor at UChicago PME, highlights how computer simulations and machine learning accelerate the design of highly selective probes, enabling faster deployment. Seth Darling of Argonne and UChicago adds that recognizing the unique molecular features of PFAS is essential to building sensors that work at trace levels common in drinking water.
In sum, this handheld PFAS detector represents a significant step toward real-time water safety monitoring. As development progresses, it may empower communities to act quickly in the face of contamination and make informed choices about the water they drink and the environment they inhabit.