A Fluorescent Composite of Carbon-Dot-Embedded Covalent Organic Frameworks for Highly Sensitive and Rapid Detection...

The excessive accumulation of biogenic amines (BAs) in aquatic products poses serious health risks, necessitating the development of rapid and sensitive detection methods. This study reports the synthesis of a novel fluorescent nanocomposite, carbon-dot-embedded covalent organic frameworks (CDs@COFs). Comprehensive characterization (TEM, XPS, FTIR, UV-Vis, and fluorescence spectroscopy) confirmed the successful fabrication of the nanocomposites, which exhibited excellent thermal and optical stability. A significantly enhanced quantum yield of 36.22% (compared with 12.92% for pure carbon dots) was obtained. As a fluorescent probe, the composite enabled the detection of nine BAs based on a fluorescence quenching mechanism. The proposed method demonstrated good linearity (1~100 ng/mL) and low detection limits of 0.58~0.98 ng/mL. The method was successfully applied to analyze tyramine in large yellow croaker, showing accurate spike recoveries ranging from 91.93% to 101.43% and excellent reproducibility (RSD < 3%). These results highlight the great potential of the developed method as a powerful tool for the rapid screening of BAs in aquatic products.