A reusable fluorescence Eu-based coordination polymer for the detection of Zr4+ ions in aqueous media

Abstract

A fluorescence 3D coordination polymer (CP) [Eu(L)_1.5(phen)(H₂O)] (1, H₂L = 9,10-anthracenedicarboxylic acid and phen = 1,10 phenanthroline) was prepared using a solvothermal method. The fluorescence sensing experiments showed that among the 12 selected metal ions, only Zr⁴⁺ ions significantly suppressed the luminescence emission intensities of 1 dispersed in aqueous media. The emission intensities of 1 and the concentrations of Zr⁴⁺ ions could be fitted well (R² = 0.99801) using the linear Stern–Volmer equation over a concentration range of 0–15 μM with a K_SV value of 53 830 M⁻¹, and subsequently a low limit of detection of 0.167 μM and a limit of quantification of 0.501 μM were obtained. We also confirmed its reusable sensing performance for Zr⁴⁺ ions. The fluorescence response of 1 to Zr⁴⁺ ions hardly changed for at least 4 cycles of the sensing test. Although, according to the literature, there are organic molecules and CPs used for the detection of Zr⁴⁺ ions, the reusable properties of these fluorescence sensing materials have rarely been reported. Therefore, 1 represents a fluorescence sensing material for Zr⁴⁺ ions with an excellent detection performance (selectivity, sensitivity, anti-interference ability and reusability). The mechanism of fluorescence quenching may be attributed to the static weak interactions between Zr⁴⁺ ions and 1.