Revolutionizing PFAS Detection with a Handheld Sensor
Per- and polyfluoroalkyl substances (PFAS) — often called “forever chemicals” — linger in water, soil, and even our bodies. New research from the University of Chicago Pritzker School of Molecular Engineering (UChicago PME) and Argonne National Laboratory has yielded a portable, handheld sensor that can detect trace PFAS in water within minutes. The breakthrough could transform how communities monitor drinking water and how agencies enforce emerging limits on toxic PFAS compounds such as PFOS and PFOA.
From Weeks to Minutes: The Promise of Portable PFAS Probes
Traditional PFAS testing relies on costly laboratory techniques like liquid chromatography/tandem mass spectrometry. These methods, while accurate, require specialized equipment and expertise and can take weeks to deliver results. The new sensor shifts that paradigm by using miniature, chip-scale sensors that translate chemical binding events into measurable electrical signals on a silicon surface.
How the Sensor Works
The device detects PFAS by letting a PFAS molecule attach to a specially designed molecular probe on the chip. This binding alters the electrical conductivity across the surface, creating a readout proportional to PFAS concentration. The challenge lay in making the sensor selective for particular PFAS chemicals, such as PFOS, amid a flood of other compounds in tap water.
To achieve selectivity, the researchers turned to machine learning. They trained algorithms to sift through thousands of candidate probes and identify those most likely to bind specifically to target PFAS molecules. A Discovery Challenge Award from the University of Chicago’s Center for Data and Computing (CDAC) helped accelerate this AI-driven probe discovery.
Validation and Real-World Readiness
In their study published in Nature Water, the team demonstrated a reversible, parts-per-trillion-level detection of PFOS in tap water. The device could detect PFOS at 250 parts per quadrillion (ppq) — roughly one grain of sand in an Olympic-sized swimming pool — aligning with the stringent concentration ranges under consideration by the U.S. Environmental Protection Agency (EPA), which recently proposed limits of 4 parts per trillion for PFOS and PFOA.
To ensure accuracy, readings from the handheld sensor were cross-validated with EPA-approved liquid chromatography/tandem mass spectrometry. The sensor maintained performance across repeated cycles of detection and rinsing, a key indicator of potential real-time, field-ready monitoring rather than a one-off laboratory experiment.
Implications for Public Health and Policy
PFAS contamination has been linked to various health concerns, including certain cancers and immune system impacts. The ability to deploy portable PFAS sensing devices could empower water utilities, first responders, and even households to assess risk quickly and make informed decisions about water use and treatment options. The researchers envision expanding the probe library to cover additional PFAS variants and, ultimately, to detect other contaminants such as antibiotics or viruses using the same platform.
Looking Ahead: Scaling and Accessibility
Chen, Ferguson, Darling, and their collaborators stress that the next steps include synthesizing new probes for a broader spectrum of PFAS and proving scalability for widespread deployment. The long-term vision is a suite of handheld sensors capable of rapid, on-site testing across drinking water systems and environmental monitoring networks, reducing reliance on centralized laboratories and enabling timely public health interventions.
As researchers continue refining the technology, the prospect of consumer-friendly water testing grows closer. If such devices reach households and local utilities, communities could monitor PFAS levels in real time and take prompt action to protect health and safety.
