Design and performance study of fluorescent molecular probes based on Europium coordination compounds

Abstract

In this study, the target compound CDA is synthesized through a nucleophilic addition reaction using 2-amino-6-chlorobenzothiazole and ethylenediaminetetraacetic dianhydride as raw materials. The structure of CDA is characterized via ultraviolet-visible (UV–Vis) and fluorescence spectroscopy, revealing its specificity for rare earth metal ions. Concentration titration, interference experiments, and reversibility tests further investigate the relationship between Eu³⁺ and the fluorescence intensity of the probe. The [CDA+Eu³⁺] system is then applied for antibiotic detection. Results demonstrate that CDA exhibits excellent specificity for Eu³⁺ in a DMSO/HEPES buffer (pH 7), with a rapid fluorescence enhancement at 617 nm upon Eu³⁺ addition. This response remains unaffected by other rare earth ions, achieving a detection limit of 0.054 µM. When detecting antibiotics, the [CDA+Eu³⁺] system specifically recognizes oxytetracycline, chlortetracycline hydrochloride, and tetracycline, inducing fluorescence quenching at 617 nm. Linear relationships are observed for these antibiotics with detection limits of 0.60, 0.48, and 0.59 µM, respectively. Interference experiments confirm that the recognition of tetracycline antibiotics is not compromised by coexisting antibiotics of other classes.