Selective Recognition and Portable Quantification of PVC Microplastics Using a Water-Soluble AIE Fluorescent Probe

Microplastic pollution, particularly polyvinyl chloride (PVC), has raised increasing environmental concern because of its persistence and potential release of hazardous additives. However, selective and rapid detection of PVC microplastics in aqueous environments remains challenging. Herein, a water-soluble aggregation-induced emission (AIE) fluorescent probe, BTPA-QM-SO3, was developed for selective staining and quantitative detection of PVC microplastics. The probe enables direct fluorescence labeling in water without pretreatment and shows a distinct turn-on response toward PVC. An ethanol-assisted washing strategy further improves the selectivity by reducing nonspecific probe adsorption on other microplastics. Combined with fluorescence imaging and image-based analysis, the method exhibits a linear response to PVC microplastics over 200 ∼ 1000 μg/mL with a detection limit of 10.52 μg/mL, and satisfactory recoveries in tap water, lake water, seawater, and industrial wastewater. Fluorescence lifetime and quantum yield measurements reveal enhanced emission efficiency after interaction with PVC, consistent with restricted intramolecular motion and suppressed nonradiative decay of the probe. Mechanistic studies suggest that stronger interfacial interactions between the probe and PVC are responsible for improved fluorescence retention and selectivity. This work provides a simple, water-compatible, and selective fluorescence strategy for PVC microplastic quantification in environmental water samples.