Blue Fluorescent Carbon Dots Synthesized From PBAT and PET Waste Plastics and Their Detection of Gefitinib

Blue fluorescent carbon dots (CDs) were synthesized in this study from poly (butylene adipateco-terephthalate) (PBAT) and poly (ethylene terephthalate) (PET) waste through a sequential carbonization and hydrothermal treatment. The nanoparticles exhibited a spherical morphology with a narrow size distribution of 1.3-2.5 nm, abundant hydrophilic surface groups, and excellent dispersibility in aqueous solution. The CDs exhibited strong blue fluorescence with a quantum yield (QY) of 7.4% and remarkable stability. The fluorescence was selectively quenched by gefitinib primarily via a Förster resonance energy transfer (FRET) mechanism. The developed sensor showed a linear detection range of 0-30 μM, a low detection limit of 0.8433 μM, and outstanding anti-interference capability against common biomolecules and structurally similar drugs. The spiked recovery rates in real samples ranged from 96.7% to 103.0%, with the relative standard deviations (RSDs) less than 3.0%, demonstrating the probe's capability for detecting gefitinib in complex practical matrices. The proposed sensor shows great potential for applications in therapeutic drug monitoring and clinical diagnostics, offering a promising solution for both environmental sustainability and analytical science.