Brilliant cresyl blue modified carbon quantum dots for sequential detection of insecticides fipronil, Fe3+, and acephate

Fipronil (FIP) and acephate (ACE) are highly toxic insecticides that pollute the environment and pose a health hazard, potentially being carcinogenic or teratogenic. Excess Fe 3+ can trigger oxidative stress and lead to organ damage. Conventional fluorescent probes can only be used for single detection, and the development of multi-target simultaneous detection methods is imminent. In this work, brilliant cresyl blue modified carbon quantum dots (B-CQDs) were synthesized using a simple one-step hydrothermal method. It was found that B-CQDs can sequentially detect multiple substances under certain conditions. Firstly, the fluorescence of B-CQD increases with the concentration of insecticide FIP, and decreases with the addition of Fe 3+ . After activation treatment with EDTA and Zn 2+ solutions, the fluorescence intensity of the system increases with the concentration of insecticide ACE. A fluorescent probe was established based on the above experimental phenomena to achieve sequence detection of FIP, Fe 3+ , and ACE, with the lower limits of detection (LODs) being 0.078 μM, 0.013 μM, and 0.055 μM, respectively. Therefore, the new method of sequence detection for multiple pesticide residues developed in this study shows great potential for application in environmental pesticide residue detection.