Fluorescence Study of the Interaction Between a Modified β‐Cyclodextrin and Metacycline–Eu³⁺ and Its Analytical Application

Abstract

A simple sensitive spectrofluorimetric method was developed for the determination of metacycline. Ethyl substituted β‐cyclodextrin (DE‐β‐CD) can remarkably enhance the fluorescence intensity of the metacycline (MC)–Eu³⁺ complex at λ = 612 nm and the enhanced fluorescence intensity of Eu³⁺ ion is in proportion to the concentration of MC. Optimum conditions for the determination of MC were also investigated. The linear range and the detection limit of this method for the determination of MC are 2.20 × 10⁻⁷–1.47 × 10⁻⁵ mol/L and 3.60 × 10⁻⁸ mol/L, respectively. The recommended method is practical and relatively free interference from coexisting substances and can be successfully applied to determination of MC in samples of serum and urine. The interaction mechanism between the complex MC–Eu³⁺ and DE‐β‐CD has been studied. The enhancement of the fluorescence at λ_em = 612 nm of Eu³⁺ ion is because of the inclusion complex MC–Eu³⁺–DE‐β‐CD.

Keywords:

• Fluorescence
• Ethyl substituted β‐cyclodextrin
• Europium (Eu³⁺)
• Metacycline (MC)
• Inclusion complex

Acknowledgments

The authors are grateful for the National Natural Science Foundation of China for its financial support. (Grant No. 20271043).