A highly stable chain-based Eu^III metal–organic framework as a turn-on and blue-shift luminescent sensor for dipicolinic acid

Abstract

The development of a rapid and selective method for the identification of dipicolinic acid (DPA), a specific biomarker in <i>Bacillus anthracis</i> spores, is of great importance for the avoidance of anthrax infection. Herein, a chain-based Eu^III metal-organic framework with the formula {[Eu₃(BTDB)₃(μ₃-OH)₃(H₂O)]·solvents}_<i>n</i> (JXUST-38, H₂BTDB = (benzo[<i>c</i>][1,2,5]thiadiazole-4,7-diyl)dibenzoic acid) was obtained using 2-fluorobenzoic acid as the pH regulator. JXUST-38 exhibits good chemical and thermal stability and can specifically recognize DPA in <i>N</i>,<i>N</i>-dimethylformamide solution through luminescence enhancement and blue-shift effects with a detection limit of 0.05 μM. Furthermore, the significant luminescence enhancement and blue shift under UV lamps are obviously observable by the naked eye. The luminescence sensing mechanism is attributed to absorbance-induced enhancement between JXUST-38 and DPA. Test paper and mixed-matrix membrane based on JXUST-38 are designed for DPA detection. In addition, the feasibility of using JXUST-38 in biosensing is discussed in detail.