Deep eutectic solvent-functionalized graphene aerogel fiber for solid-phase microextraction of p-phenylenediamine and quinone derivatives in environmental waters.

A new deep eutectic solvent-functionalized chitosan-reduced graphene oxide aerogel (DES@CS@RGO) powder was synthesized and utilized as a fiber coating in direct immersion solid-phase microextraction (DI-SPME) for the determination of p-phenylenediamines (PPDs) and its quinone derivatives (PPD-Qs) in environmental water samples. The fiber coating exhibited a three-dimensional porous structure and multiple adsorption interactions, including π-π stacking and hydrogen bonding. Coupled with gas chromatography-mass spectrometry (GC-MS), the developed SPME method achieved low limits of detection (0.13-1.12 pg/mL), wide linear ranges (5-1000 pg/mL), excellent relative recoveries (83.2%-103.3%), and good precision (RSDs ≤ 10.3%). The synthesized fiber demonstrated outstanding reusability, maintaining 77.4%-90.9% of its efficiency after 90 cycles. Environmental water sample analysis revealed the presence of PPDs/PPD-Qs in urban surface waters, verifying the method's environmental applicability. This work presents a sensitive, reproducible, and eco-friendly platform for monitoring trace aromatic amines in complex matrices.