A dual reference ion-imprinted ratiometric fluorescence probe for simultaneous detection of silver (I) and lead (II)

We describe a dual reference ion-imprinted ratiometric fluorescence probe for simultaneous detection of Ag+ and Pb2+. Carbon dots (CDs) and gold nanoclusters (AuNCs) were adopted for fluorescence signal output. To improve the conversion efficiency from molecular recognition to fluorescence signal output, functional groups on the surface of fluorescence nanoparticles were used to form a chelate with template ions during polymerization. During the detection of Ag+, the CDs were quenched, while AuNCs remained stable as the reference. For Pb2+ detection, AuNCs were the response signal, and CDs were the reference. Under optimal conditions, (ICDs)0/(IAuNCs) displayed a good linear relationship with the concentration of Pb2+ from 50 to 900 nM with detection limits of 26 nM; (IAuNCs)0/(ICDs) had a good linear relationship with the concentration of Ag+ from 0.2–12.5 μM with a detection limit of 86 nM. Using this dual reference strategy, Ag+ and Pb2+ can be detected simultaneously in real water samples with satisfactory recoveries. This work enables high-throughput detection based on fluorescence signal output, which saves detection time and costs.