Aminated Carbon Nanofiber-Mediated Nanoconfined Liquid Phase Nanoextraction Coupled with Py-GC/MS for Sensitive Determination of Polystyrene Nanoplastics

Nanoplastics pose severe ecological and human health risks due to their high reactivity and bioaccumulation potential, but their efficient extraction and precise detection remain challenging. Herein, a novel integrated method combining nanoconfined liquid phase nanoextraction (NLPNE) based on aminated carbon nanofibers/ carbon fibers (NH ₂ -CNFs/CFs) with pyrolysis-gas chromatography-mass spectrometry (Py/GC-MS) was developed for the sensitive determination of polystyrene (PS) nanoplastics in aqueous samples. NLPNE plays a pivotal role: the nanoconfined spaces formed by entangled CNFs accelerate PS mass transfer via short-range diffusion, while amino groups enhance specific electrostatic interactions with negatively charged PS, achieving rapid and selective pre-enrichment. Optimized with acetonitrile as the nanoconfined solvent, the method reaches extraction equilibrium quickly, following pseudo-first-order kinetics and Langmuir monolayer adsorption. Direct Py-GC/MS analysis using styrene trimer (m/z=312) as the marker yields a low detection limit of 0.56 μg/L. The method provided a novel technical solution for the detection of nanoplastics in complex matrices and facilitating future studies on their environmental behaviors.