Single-Molecule Electrochemical Analysis of Per- and Polyfluoroalkyl Carboxylic Acid Isomers

• • Achieved near 100% accurate identification of seven PFCA isomers using engineered Aerolysin nanopores (WT, R220N, R220Q), demonstrating the capability to resolve structural isomers with minimal differences. • • The method operates without standard reference compounds, overcoming a major bottleneck in conventional PFAS analysis, which is critical for nontargeted screening and rapid risk assessment. • • Feature selection enabled high classification accuracy even with low data volumes, reducing computational and experimental burden, which is essential for real-time environmental monitoring. • • The study establishes a linear relationship between molecular volume and current blockade, providing a quantitative basis for standard-free analysis of PFCAs, with potential extension to other persistent organic pollutants.