Bubble Nucleation-Based Electrochemical Sensor for Detection of per- and Polyfluoroalkyl Substances (PFAS) in Water

Here, we present a proof-of-concept electrochemical detection method for detection of per- and polyfluoroalkyl substances (PFASs) in water. PFASs are persistent and globally distributed environmental contaminants. The strong carbon-fluorine bonds of PFASs make them resistant to physical and metabolic degradation leading to bioaccumulation and adverse health outcomes in humans and wildlife. The quantitative determination of PFASs in environmental matrices has been dominated by the use of HPLC-negative electrospray ionization- tandem MS. However, the high purchase and maintenance costs limit the availability of this method for routine on-site screening analyses. Therefore, there is a critical need to develop a low-cost, sensitive, portable method for detection of PFASs in water. Our detection method is based on the high surface activity of PFASs which lowers the energy barrier for bubble nucleation. We developed a sensitive electrochemical transducer that reports the change of surface tension in the form of an electrical current which is directly related to the concentration. The limit of detection of our detection method is 20 nM (or ~10 μg/L) with a dynamic range of three orders of magnitude. With the addition of a preconcentration step, our method achieves the limit of detection of interest:14 pM (or 70 ng/L, which is recommended by the U.S. Environmental Protection Agency for PFOS and PFOA—the two dominant PFAS contaminants— in drinking water individually or combined.)