Development of a High-Performance Fluorescent Probe for Food Safety: N,Si-CDs for Detecting Tetracycline and Chloramphenicol

Tetracycline (TC) and chloramphenicol (CAP), which are types of antibiotics, have been strictly regulated or even banned in many countries due to their potential toxicity to humans and the risk of promoting antibiotic resistance when residues remain in food. Therefore, the development of efficient detection methods for these antibiotics is of great significance. This study focuses on residues of antibiotics in the context of food safety. We used N-acetyl-L-cysteine and 3-aminopropyltriethoxysilane (APTES) as precursors to synthesize nitrogen and silicon co-doped carbon dots (N,Si-CDs) via a one-step hydrothermal method, which exhibit both high hydrophilicity and stable fluorescence properties. This method breaks through the limitations of traditional single-target detection and achieves high-sensitivity detection of TC and CAP in the same probe system, with linear ranges of 10–30 µM (TC) and 10–40 µM (CAP), respectively, and detection limits as low as 0.45 µM (TC) and 0.54 µM (CAP). We developed a visual detection system using the Color Picker application to quantify antibiotic concentration through RGB signals (blue channel intensity) and achieve rapid on-site screening. This probe has good selectivity and resists interference, successfully detecting TC and CAP in real food samples, showing good recovery rates and practical applicability.