Luminol-Eu-based ratiometric fluorescence probe for highly selective and visual determination of tetracycline

In this work, a ratiometric fluorometric method based on luminol-Europium complex (luminol-Eu) was constructed for the detection of tetracycline (TC). Luminol-Eu, synthesized by self-assembly reaction, displayed a strongly emission peak at 453 nm under excitation at 360 nm which was derived from the aggregation-induced emission (AIE) of the luminol-Eu. In the present of TC, the fluorescence of luminol-Eu at 453 nm was quenched based on inner filter effect (IFE). Meantime, the characteristic emission peak of Eu3+ at 626 nm can be observed thank to antenna effect (AE). Therefore, we proposed a ratiometric fluorometric method for detection of TC, which allowed detection of TC from 0.5 to 80 mu M with the detection limit of 39 nM. In addition, the luminol-Eu-based test paper was prepared for visual semi-quantitative detection of TC in real samples based on the color of luminol-Eu change from blue to red under 365 nm ultraviolet light. All of those results indicated that the ratiometric fluorometric strategy was fast, sensitive, and visual for detection of TC.

Automated summary

A ratiometric fluorometric method based on luminol-Europium complex was developed for the detection of tetracycline, showing quenching of fluorescence at 453 nm due to inner filter effect in the presence of TC and observation of Eu3+ emission peak at 626 nm thanks to antenna effect. This strategy is fast, sensitive, and visual for TC detection, allowing for detection from 0.5 to 80 mu M with a detection limit of 39 nM, and demonstrating color change from blue to red in real samples using luminol-Eu-based test paper under 365 nm ultraviolet light.