Metal organic framework of MOF-5 with hierarchical nanopores as micro-gravimetric sensing material for aniline detection

Aromatic amine such as aniline is one kind of carcinogenic substances that needs to be detected at low concentration. To sense trace level aniline, high performance sensing material is of great importance. Herein, metal organic framework of Zn4O(1,4-benzenedicarboxylate)3 (commonly abbreviated as MOF-5) with abundant hierarchical nanopores is firstly employed as mass-type sensing material for low concentration aniline detection. By using one typical micro-gravimetric transducer of resonant microcantilever, the aniline-adsorbing induced mass-addition of MOF-5 is transformed to the detectible sensing signal of frequency shift. Based on resonant microcantilever with mass resolution of 1.5 pg/Hz, the fabricated sensor exhibits good sensitivity for aniline detection. The limit of detection is better than 1.4 ppm, and the selectivity is satisfactory to nine kinds of common interfering gases. The three-cycle repeatability of the sensor is also investigated with a relative standard deviation (RSD) of 4%. After 20 days, the sensor only shows a negligible response degradation which represents a good reproducibility. Materials Studio simulation results manifest that 1,4-benzenedicarboxylic ligand in MOF-5 crystals is the preferential site for aniline molecules adsorbing.