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

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 (R-2 = 0.99801) using the linear Stern-Volmer equation over a concentration range of 0-15 mu M with a K-SV value of 53 830 M-1, and subsequently a low limit of detection of 0.167 mu M and a limit of quantification of 0.501 mu M 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.