Multicomponent Fluorescent MOF-Based Bifunctional Sensor for the Visual Detection of 2,4,6-Trinitrophenol and Nitrofurantoin

The chemical sensors based on luminescent MOFs (LMOFs) have attracted widespread attention in the sensing field due to their high sensitivity and rapid response. However, bifunctional sensors that can simultaneously detect nitro-explosives and antibiotics have rarely been developed among numerous synthesized LMOFs. Here, we report a 3D Cd-based LMOF with four coexisting components, defined as CUST-534, with the formula [Cd(4Cl-BDC)0.5(STDC)0.5L]n (4Cl-BDC = tetrachloroterephthalic acid, STDC = 4,4′-stilbenedicarboxylic acid, and L = 9,10-bis(N-benzimidazolyl)anthracene). Thanks to the conjugated structure of the anthracene nitrogen-containing ligand and coordination effect, CUST-534 exhibits bright blue light emission, enabling high sensitivity and selectivity in detecting 2,4,6-trinitrophenol (TNP) and nitrofurantoin (NFT) through a quenching effect. The lowest detection limits for TNP and NFT are 0.20 and 0.23 ppm, respectively, which surpass those of many previously reported fluorescent sensing materials. In addition, considering the difficulty of collecting the MOF powder, a portable fluorescent test strip was successfully constructed by combining it with filter paper. Accurate conversion of color and RGB coordinates can be achieved with the assistance of the application color recognizer on the smartphone. This strategy is easy to operate and efficient, demonstrating its potential in practical applications.