Comparison of ultrasonic vs mechanochemistry methods for fabrication of mixed-ligand Zn-based MOFs for electrochemical determination of luteolin

Looking for green synthesis methods is the main direction of MOFs research in the green chemical industry to meet large-scale preparation of modified materials suitable for highly active electrodes. In this study, 1,3,5-benzenetricarboxylic acid (1,3,5-H3BTC) and 4,4'-bipyridine (4,4'-Bpy) were used as ligands. The micro-nano structure mixed-ligand Zn-MOFs compounds, [Zn(bpy)(Hbtc)(H2O)]n·3nH2O prepared by ultrasonic and mechanochemical method were marked as Zn-MOF-U and Zn-MOF-M, respectively. The construction of the as-prepared mixed-ligand Zn-MOFs modified carbon paste electrodes (Zn-MOF/CPE) for luteolin (LUT) detection are then studied. Different preparation methods lead to differences in micro-structure, in which lath-shaped Zn-MOF-U has higher electrochemical sensing luteolin activity than bulk-shaped Zn-MOF-M. The current signal of Zn-MOF-U/CPE was linear with the concentration of LUT in the range between 0.005−1.0 and 1.0−10 μM with a sensitivity of 9.70 and 15.6 μA·mM−1·cm−2, respectively, with the limit of detection (LOD) of 3 nM. This study provides a green routes for the simple large-scale synthesis of mixed-ligands MOFs materials and the sensitive sensing detection of small biomolecules.