Novel ratiometric fluorescence sensor for organophosphorus pesticides via carbon dots supported zirconium-based metal organic frameworks

Given the potential adverse effects of organophosphorus pesticides (OPPs) on living organisms, it is imperative to explore sensing technologies that demonstrate high sensitivity and selectivity for OPPs detection. In this regard, a novel ratiometric fluorescence probe has been developed, which employs carbon dots integrated within zirconium (Zr)-based metal-organic frameworks (MOFs), specifically PCN-224@CDs, for the determination of OPPs. The probe achieves precise recognition of phosphorus group sites in OPPs through targeted interactions between the active Zr centers and the phosphorus groups, and fluorescence resonance energy transfer (FRET) occurring between carbon dots and PCN-224. Subsequent analyses conducted through Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and calculations of adsorption energy further corroborated the occurrence of electron transfer between organophosphorus molecules and Zr groups. Under optimal conditions, the fluorescence intensity exhibited a linear correlation with the concentrations of malathion, phoxim, chlorpyrifos, and omethoate with recovery rates in celery and leek samples ranging from 75.51% to 115.74%. This ratiometric fluorescence assay offers a reliable methodology and presents a promising avenue for the advancement of trace risk detection technologies, showcasing exceptional analytical reliability and practicality.