PET-featured fluorescent test papers with smartphone platform based on chitosan carbon dots for visual detecting chloramphenicol in animal-derived foods

Conventional methods for chloramphenicol (CAP) detection often rely on sophisticated instrumentation and complex sample pretreatment, limiting their applicability for rapid on-site screening. Herein, a highly sensitive and selective fluorescent probe based on chitosan-derived carbon dots (CS-CDs) is developed via a one-step hydrothermal synthesis. The as-prepared CS-CDs exhibit a high quantum yield of 44.5% and excellent photostability. The fluorescence quenching toward CAP is attributed to a photo-induced electron transfer mechanism. The proposed sensing platform demonstrates a linear detection range from 0.1 to 160 μg L −1 with a detection limit as low as 0.03 μg L −1 , which is well below the international residue limits. To address the demand for point-of-care testing, portable test strips integrated with smartphone-based RGB analysis are fabricated, enabling visual semi-quantitative detection of CAP in animal-derived foods and demonstrating the potential of carbon dot-based sensors for rapid on-site antibiotic screening.