Bimetallic CoZn-MOFs easily derived from CoZn-LDHs, as a suitable platform in fabrication of a non-enzymatic electrochemical sensor for detecting glucose in human fluids

Abstract In the present study, an in-situ, two-step, highly controllable, fast, green, and facile strategy for fabricating the bimetallic cobalt-zinc-based metal-organic frameworks (MOFs) is employed for designing a non-enzymatic glucose sensing platform. The structural characterization, as well as the phase investigation of materials in each step, are assessed by X-ray diffraction, energy-dispersive X-ray spectroscopy, elemental mapping, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. Furthermore, the electrocatalytic activity of the CoZn-BTC/GC fabricated electrode toward the electro-oxidation of glucose is examined by various electrochemical techniques, including cyclic voltammetry, amperometry, and chronoamperometry. Moreover, from the analytical points of view, the as-prepared modified electrode exhibited two distinct linear dynamic ranges of 0.001 − 0.255 mM and 0.255 − 2.53 mM with a sensitivity of 1218 μA mM−1 cm-2, and 510 μA mM−1 cm-2, respectively. Besides, the proposed sensor also demonstrated outstanding selectivity against iso-structures and co-existence interferences, high long-term durability, rapid response (1.3 s), excellent poisoning resistance against chloride ions, good repeatability and reproducibility toward glucose electro-oxidation. In addition, the detection limit value of CoZn-BTC/GCE, based on the signal to noise ratio of 3 is obtained to be 4.7 μM. Furthermore, the limit of quantitation for the present platform is calculated to be 15.6 μM. Next the structural properties and electrochemical response of the as-prepared modified electrode were compared to its corresponding mono-metallic and LDHs. Finally, in order to demonstrate the practical application of the modified electrode and evaluate its capability for glucose measurements in real physiological specimens, the glucose is successfully measured in human blood serum, urine, and saliva samples, without any sample pre-treatment.