Dual-readout performance of Eu-doped nanoceria as a phosphatase mimic for degradation and detection of organophosphate

Eu 3+ -Doped nanoceria (Eu:CeO 2 ) with self-integrated catalytic and luminescence sensing functions was synthesized by a simple and gentle one-pot method to build a dual-readout nanozyme platform for organophosphate compound (OPC) sensing in this work. The catalytic degradation of the model substrate of OPC, p -nitrophenyl phosphate ( p -NPP), by as-prepared Eu:CeO 2 can be completed in 2 min with little influence of temperature and pH values, highlighting the advantages of Eu:CeO 2 as an artificial enzyme for dephosphorylation. Most importantly, the characteristic red emission of Eu 3+ (592 nm) from Eu:CeO 2 can be quenched by p -NPP, accompanied by a color change from colorless to yellow. Based on this, linear ranges of 4-50 μM with a detection limit of 3.3 μM and 1-20 μM with a detection limit of 0.6 μM for p -NPP were obtained by colorimetric and fluorescence methods, respectively. Furthermore, the fluorescence strategy was effectively applied to the determination of ethyl para -nitrophenyl (EPN), one of the most commonly used pesticides, with a detection limit of 5.86 μM. The proposed strategy was also successfully applied to the assay of p -NPP and EPN in real water samples, showing great application prospects in detecting OPC in the environment. A novel dual-readout analytical platform for degradation and detection of p -NPP was conveniently established using Eu:CeO 2 .