A fluorescent probe based on a luminescent metal–organic framework for the sensitive detection of histamine in aquatic products

An effective way to prevent histamine poisoning is to assess the safety of aquatic products, and hence, developing a new method for detecting histamine is particularly important. In this study, a fluorescence probe (AgNPs@PCN-224) was constructed for the sensitive detection of histamine by utilizing the mesoporous structure of a zirconium porphyrin metal-organic framework (PCN-224) loaded with silver nanoparticles (AgNPs). Because PCN-224 and AgNPs were close to each other, there was a fluorescence resonance energy transfer between the two substances, resulting in fluorescence quenching. At this point, under the action of diamine oxidase, the decomposition product of histamine (hydrogen peroxide) etched the silver nanoparticles onto the surface of PCN-224, and the fluorescence of PCN-224 was recovered. Under optimal conditions, it was confirmed that the fluorescence intensity of the probe was positively correlated with the histamine concentration in the range of 10-100 μM, with a correlation coefficient of 0.9527, and the detection limit was calculated to be 0.033 nM. The detection performance for hydrogen peroxide was also investigated, and the results demonstrated that the probe was suitable for dual-substance detection of both histamine and hydrogen peroxide. Finally, when used for the detection of grass carp samples, it was found that the recovery rate ranged from 98% to 110%, with a relative standard deviation below 8%. The findings confirmed the reliability of the AgNPs@PCN-224 fluorescent probe established in this study for the detection of histamine in aquatic samples.