Two dye-encapsulated triple-emitting naphthalene-based Zr-MOFs for tunable white-light emission and dual mode detection of inorganic ions

Abstract

A series of novel dual-dye-loaded tunable triple-emission colorimetric fluorescent BPEA&Rh6G@DUT-52 (B&R@D) probes was prepared using an in situ encapsulation method, in which the B&R@D6 probe achieved white fluorescence emission with CIE chromaticity coordinates of (0.33, 0.32) and was used for the quenching and colorimetric detection of Fe³⁺ and Cr₂O₇²⁻ and the colorimetric detection of NO₂⁻ and IO₃⁻. When analytes come into contact with the surface of B&R@D6, resonance energy transfer or electron transfer occurs, resulting in relative changes in the three emission peaks. Good linear relationships were established between the fluorescence intensities of the B&R@D6 probe and the concentrations of 0.025–0.5 mM (Fe³⁺) and 0.005–0.1 mM (Cr₂O₇²⁻) with detection limits of 2.8 μM and 18.5 nM, respectively. B&R@D6 was further applied in the detection of Fe³⁺ and Cr₂O₇²⁻ in three actual water samples with recoveries ranging from 101.5% to 114.1% and 86.8% to 100.3%, respectively, showing the practical potential of this method. In addition, a B&R@D6 portable fluorescent test paper was constructed for the in situ dual-mode detection of Fe³⁺, Cr₂O₇²⁻, NO₂⁻ and IO₃⁻. This work demonstrates the detection capabilities of triple-emitting white fluorescent probes toward ions in terms of multi-target and multi-detection modes.