Novel alcohol vapour sensor based on the mixed-ligand modified MOF-199 coated quartz crystal microbalance

Alcohol vapour sensors can be used in many fields, such as food quality monitoring, etc. Herein, we developed an alcohol vapour sensor based on the quartz crystal microbalance (QCM) technology. A modified metal-organic frameworks (MOFs), m-MOF-199 was coated on the QCM electrode surface. The different coating methods, including drop coating, spin coating and electrospray were used for preparing a thin film on the surface of the QCM electrode. MOF-199 was modified by mixed-ligand strategy in which benzotriazole ligand was introduced into the structure of MOF-199 and characterised by FT-IR, XRD, BET and FE-SEM techniques. The smaller dimension of m-MOF199 led to a better thin film and enhanced QCM sensor efficiency. In order to evaluate the QCM sensor, ethanol was used as a model compound. The developed ethanol sensor showed two linear ranges in the concentration between of 0.5-30 mg L-1 and 30-300 mg L-1 with a 0.1 and 0.5 mg L-1, LOD and LOQ, respectively. The relative standard deviation (RSD %) of measurements was less than 10%. The developed sensor could be applied for various applications including food, environmental and bioanalysis.