ZnO@MIPs-NR ratiometric fluorescent probe for ultra-sensitive on-site tiletamine detection

The abuse of tiletamine has emerged in many countries around the world. In this study, a ratiometric fluorescence probe was innovatively proposed for detecting of the anesthetic tiletamine by combining ZnO QDs-based molecularly imprinted polymers (ZnO@MIPs) and Nile blue oxazone (Nile Red, NR). The ZnO@MIPs constructed by sol-gel method exhibit strong green fluorescence emission at 510 nm, which can be selectively quenched in the presence of tiletamine. Nile red with an emission peak of 630 nm was used as an internal reference signal to assemble the ratiometric fluorescence probe (ZnO@MIPs-NR). Upon gradual introduction of tiletamine into the detection system, the fluorescence intensity of Nile Red at 630 nm (I₆₃₀) remains unchanged under 350 nm excitation, while the fluorescence intensity of ZnO QDs at 510 nm (I₅₁₀) decreases considerably. By monitoring the reduction in the I₅₁₀/I₆₃₀ ratio, the probe achieved rapid and sensitive detection of tiletamine within the concentration range 1-500 ng·mL^-1, with limit of detection (LOD) of 0.3 ng·mL^-1. In addition, the effects of potential interfering substances were evaluated, and the ZnO@MIPs-NR probe demonstrated successful application in detecting tiletamine in both spiked blood samples and forensic case samples. Overall, the excellent sensitivity and great fluorescence stability make the ZnO@MIPs-NR probe promising in the fields of drug monitoring and environmental chemistry.