A ratiometric fluorescence sensor for triticonazole based on the encapsulated boron-doped and phosphorous-doped carbon dots in the metal organic framework.

In this work, boron-doped carbon dots (B-CDs) with blue fluorescence and phosphorous-doped green emitting CDs (P-CDs) were encapsulated into zeolitic imidazolate framework-8 (ZIF-8) to prepare a dual-emission ratiometric fluorescence sensor for triticonazole. The B-CDs/P-CDs@ZIF-8 composite exhibited two emission peaks at 440 nm and 510 nm under a single wavelength excitation of 385 nm that respectively belong to B-CDs and P-CDs. In the presence of triticonazole, the fluorescence intensity of B-CDs remarkably declined while that of P-CDs remained unchanged. With increasing concentration of triticonazole, the fluorescence color of the ratiometric probe progressively changed from blue to green. Under the optimized conditions, B-CDs/P-CDs@ZIF-8 probe showed a high sensitivity with a linear range from 10 to 400 nM and a detection limit of 4.0 nM for triticonazole. The probe not only has an improved sensitivity through the accumulation of analyte molecules into the metal-organic framework but also has the advantages of ratiometric fluorescence measurements in terms of precision and accuracy. The applicability of the sensor was evaluated in the analysis of water and fruit juice samples.