Rapid and Accurate Detection of Perfluorooctanesulfonic Acid in Environmental Samples via Chemiresistive Sensor Integrating Molecular Imprinting and Fluorine–Fluorine Interactions

Key findings from this study

• The study found that fluorine-fluorine interactions combined with molecular imprinting cavities enable selective PFOS detection at 1.3 ng·L⁻¹.
• The authors report that the sensor differentiated perfluoroalkyl compounds with different carbon-fluorine chain lengths and functional head groups.
• The researchers demonstrate that environmental validation in contaminated water and soil samples achieved concordance with mass spectrometry reference methods.

Overview

The study presents a chemiresistive sensor for detecting perfluorooctanesulfonic acid (PFOS) in environmental samples. The sensor integrates a polydopamine-based molecularly imprinted polymer with a perfluorinated probe assembled on a Ti3C2Tx film. Recognition of PFOS occurs through dual mechanisms: molecular imprinting and fluorine-fluorine interactions between the probe and target analyte.

Methods and approach

The researchers engineered a dual-recognition interface on a self-assembled Ti3C2Tx electrical transfer channel. Polydopamine MIP cavities and perfluorodecylthiol probes were integrated to capture PFOS. Binding events produced measurable conductivity changes in the Ti3C2Tx layer. Density functional theory calculations elucidated weak interactions between fluorine atoms and binding sites for hydrogen bonding and electrostatic interactions. The sensor was validated against LC-MS/MS analysis in water and soil samples from fluorine chemical industrial parks.

Results

The sensor achieved a detection limit of 1.3 ng·L⁻¹ with an average selective factor of 12.0. This sensitivity enabled differentiation of perfluoroalkyl sulfonic acids with varying C-F chain lengths and head groups. Density functional theory confirmed weak F···F interactions between PFDT and PFOS, alongside hydrogen bonding and electrostatic interactions within the imprinted cavities. Environmental sample analysis showed strong agreement with LC-MS/MS reference measurements, validating the sensor's practical applicability in field settings.

Implications

The dual-recognition mechanism combining molecular imprinting with secondary interactions offers a template for developing selective sensors targeting structurally similar fluorinated compounds. The approach addresses analytical challenges in detecting persistent organic pollutants at environmentally relevant concentrations. Chemiresistive transduction enables rapid on-site screening without laboratory infrastructure, supporting monitoring programs in contaminated regions.

Scope and limitations

This summary is based on the study abstract and available metadata. It does not include a full analysis of the complete paper, supplementary materials, or underlying datasets unless explicitly stated. Findings should be interpreted in the context of the original publication.