Real-time PFAS Sensing for Enhanced Site Remediation

Poly- and per-fluorinated alkyl substances (PFAS), a group of chemicals known to cause detrimental environmental and health effects, have been linked to the use of AFFF at Air Force Bases across the US. To ensure appropriate remediation and prevent further exposure, hundreds to thousands of samples must be sent for analysis to an accredited laboratory. This costs $200 - 500/sample with wait times up to a month for results. This results in large lag times before site managers can make decisions on how to handle a potentially contaminated site. The development of a cost-effective, real-time, networkable PFAS sensor would give site managers the ability to screen samples immediately and act, reducing costs and exposure to the surrounding environments. This technology could be paired with remediation efforts since there is no current technology for on-site evaluation of remediation efficiency or effectiveness. This work proposes pairing sensing and remediation technologies. Molecularly imprinted polymer (MIP) based electrochemical sensor for cost-effective, real-time, and networkable PFAS sensing will be investigated as a relevant technology for PFAS remediation projects as US Air Force installations. MIPs are designed with a specific target molecule in mind, in this case PFOS. During synthesis, the MIP creates spaces selective towards the chemical properties of the chosen molecule. Once the MIP if formed, the imprint can be removed creating holes in the MIP. These holes are filled when the MIP contacts the target molecule during analysis. As the holes fill, access to the electrode surface is blocked, impeding the ability to measure current. The reduction in current is logarithmically related to concentration of the target molecule in solution. So far, we have demonstrated reproducible sensing of PFOS down to single ppt. Expansion to include PFOA is in our immediate future, but nearly all polyfluorinated alkyl acids (PFAA) should be imprintable for sensing. Multiple screen-printed electrodes can be multiplexed to provide detection of several PFAS at once.