Fast cathodic reduction electrodeposition of a binder-free cobalt-doped Ni-MOF film for directly sensing of levofloxacin

To circumvent the binder’s adverse effect on the performance of electrochemical sensor and improve the analysis efficiency, a binder-free cobalt-doped Ni-MOF (Co/Ni-MOF) film, with honeycomb-like structure, is fast electrodeposited on glassy carbon electrode (GCE) by cathodic reduction. No conductive agent added, the Co/Ni-MOF/GCE can be directly used as a sensor for levofloxacin (LEV) determination. Under the optimal condition, a wider linear range of 0.1 μM–500 μM LEV is obtained with the limit of detection (LOD, 3S/N) being 22 nM and the sensitivity of 2.85 μA μM−1 cm−2. Further, when being used to analysis of LEV in eye drop and spiked milk, satisfactory recoveries of 94.0%–108.2% are achieved. Particularly, benefiting of the synergistic effect of Co2+ and Ni2+, as well as and the binder-free film, the sensor exhibits an excellent sensitivity and a robust long-term stability. This work develops a facile and efficient strategy to synthesis of Co and Ni based MOF film, and provides them a new way in electrochemistry application.