Rapid Single-Step Detection of Polyfluoroalkyl Substances (PFAS) Using Electropolymerized Phenoxazine Dyes

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Per- and polyfluoroalkyl substances (PFAS) are persistent, ubiquitous environmental contaminants subject to increasing regulation.
• Current analytical methods for PFAS are often complex, time-consuming, and costly.
• There is a critical need for rapid, sensitive, and affordable PFAS detection technologies.

Purpose of the Study:

• To develop and validate a novel electrochemical sensing platform for the detection of PFAS.
• To achieve sensitive quantification of representative PFAS, such as PFOS and PFOA, at environmentally relevant concentrations.
• To demonstrate the potential for a rapid, inexpensive, and field-deployable method for PFAS analysis.

Main Methods:

• Electropolymerization of Meldola blue (MB) to form a stable redox film (epMB) on an electrode surface.
• Utilizing the amino sites on epMB for electrostatic interactions with PFAS molecules.
• Monitoring concentration-dependent changes in the electrochemical signal (epMB/epMB+) upon PFAS binding.
• Assessing sensor selectivity against common environmental interferents.

Main Results:

• The developed sensor achieved limits of detection of 0.4 ppt for PFOS and 1.65 ppt for PFOA, meeting EPA regulatory limits.
• The sensor demonstrated high selectivity for long-chain PFAS over interfering substances like humic acid, salts, and metal ions.
• The method allows for rapid, single-step quantification with potential for measuring a total PFAS index.

Conclusions:

• The phenoxazine-based electrochemical sensor provides a rapid, sensitive, and cost-effective approach for PFAS detection.
• This technology addresses a significant challenge in environmental monitoring by simplifying PFAS analysis.
• The sensor shows promise for practical field deployment in environmental monitoring and regulatory compliance.