Fluorescence detection of difloxacin in milk using blue light-emitting carbon dots

Developing effective methods to detect contamination in milk during production, processing, and storage is quite important but challenging. Difloxacin (DIF), due to its great potential in veterinary medicine for the treatment of bacterial infections, is one of the most common organic contaminants in milk, posing a potential and significant threat to human health. However, there is a lack of high-performance means for the effective in-situ monitoring of DIF. Herein, we have successfully achieved high-sensitivity and high-selectivity fluorescence detection of DIF in milk using blue-luminescent carbon dot (b-CD) materials prepared. When a certain amount of DIF is present in the milk, titrating it into the reagent results in a significant quenching of the fluorescence. The calculated Ksv value is 1698.7 M−1, and the detection limit is 1.77 × 10-5 M, which is better than previously reported. Crucially, the preparation cost of these fluorescent carbon dots is low, making it hopeful to develop them into specific fluorescent detection products. They are potentially valuable for practical application in the detection of DIF in infant milk products and other emulsions.