Time: The potentially powerful, often-overlooked variable in electrochemical sensing of per- and polyfluoroalkyl substances

Abstract

Modern electrochemistry places a heavy emphasis on the importance of thermodynamic measurements for environmental sensing. While most electrochemical sensors require some type of binding mechanism, analytes do not bind to sensors instantaneously; the binding process takes time, suggesting that we must examine reaction kinetics as well. With emerging environmental pollutants of concern, such as per- and polyfluoroalkyl substances (PFAS), electrochemists must consider the kinetic relationship between the electrochemical sensor and the analyte. Various types of environmental electrochemical sensors, such as enzymes, antibodies, aptamers, and molecularly imprinted polymers (MIPs), exist. Each type of sensor can be used in the environment, but MIPs have recently demonstrated strong potential to qualitatively and quantitatively detect and identify PFAS species at the earliest onset of environmental contamination. Additionally, the mathematical and experimental approaches to MIP binding have room to expand beyond the thermodynamic isotherm models and into a time-dependent kinetic model.