Polymer-coated electrode detects PFAS in water

Per- and polyfluoroalkyl substances (PFAS) are persistent pollutants that have contaminated drinking-water supplies around the world. Scientists and regulators would like to easily detect these substances near the source of contamination as soon as they appear and continuously track them in the field. Jeffrey E. Dick of the University of North Carolina at Chapel Hill and colleagues have now assembled the basic components of an electrode sensor that one day could provide real-time remote sensing of PFAS in waterways (ACS Sens. 2020, DOI: 10.1021/acssensors.0c01894). The team coated electrodes with a polymer made to capture perfluorooctanesulfonate (PFOS), one of the most widespread PFAS. When PFOS molecules bind to the polymer, they reduce the current flowing through the electrode in proportion to PFOS concentration. The researchers tested the sensor on PFOS-spiked samples of river water and found that it detected PFOS at levels as low as 3.4 picomolar, well below the US Environmental Protection Agency’s health advisory level of 140 pM. “The next step is to optimize the selectivity of the polymer to PFOS,” Dick says.