Synthesis of a dual-emission fluorescent probe using graphitic carbon nitride as a carrier for the rapid detection of mesosulfuron-methyl

Abstract

Pesticides play an irreplaceable role in ensuring increased food production and income, but the overuse of pesticides can also pose a threat to food and environmental safety. A novel dual-emission fluorescent probe was developed for the facile and accurate detection of sulfonylurea herbicides. A Förster resonance energy transfer system, based on N-doped carbon dots (N-CDs) and thioglycolic acid-capped cadmium telluride quantum dots (TGA-CdTe QDs) as energy donor–acceptor pairs, was established using graphitic carbon nitride (g-C3N4) as a substrate and successfully applied for the micro-detection of mesosulfuron-methyl (Mes). The CDs-CdTe/C3N4 probe exhibits emission peaks at 445 and 593 nm with strong fluorescence intensity under single-wavelength excitation. Mes was shown to significantly decrease the fluorescence intensity of each emission peak via different quenching mechanisms, and the degree of quenching was proportional to Mes concentration. The linear range of fluorescence measurement was 0–90 µM, with limits of detection at 1.3 µM (445 nm) and 0.8 µM (593 nm). The dual-emission fluorescent probe exhibited excellent selectivity for Mes compared with the other eleven herbicides. The fluorescent probe has a satisfying detection performance in environmental water samples and wheat samples, and has potential application in the portable detection of pesticide residues.