Innovative homogeneous voltammetric sensing strategy for fluoroquinolone antibiotics based on Fe-MOF nanozyme and graphdiyne/carbon nanotubes composites

• A homogeneous voltammetric (HVC) sensing strategy for fluoroquinolone antibiotics (FQs) was designed for the first time. • The peroxide-like catalytical activity of Fe-MOF nanozyme was enhanced via its chelation with FQs. • The as-prepared graphdiyne/carbon nanotubes can amplify greatly the response signal. • A low detection limit and a wide linearity were obtained for ciprofloxacin . • The as-designed HVC sensing platform exhibits universal sensing capability for other FQs targets. For achieving sensitive and efficient detection of fluoroquinolone antibiotics (FQs), herein an innovative homogeneous voltammetric (HVC) sensing strategy was proposed by synthesizing iron-based metal organic framework (Fe-MOF) as nanozyme and graphdiyne/carbon nanotubes (GDY/CNTs) as signal amplification. For this proposal, the abundant Fe 3+ on Fe-MOF surface can coordinate with the adjacent carbonyl and carboxyl groups of FQs in homogeneous solution via chelation reaction, thereby accelerating the Fenton reaction to enhance peroxide-like activity of Fe-MOF which can catalyze o-phenylenediamine oxidation to generate diaminophenazine (DAP). In order to amplify the response signal and improve the sensing sensitivity, the GDY/CNTs composite exhibited the synthetical advantages of GDY and CNTs was prepared and modified on the electrode surface. The results showed that the reduction current intensity of DAP measured by GDY/CNTs electrode was linearly related to the level of FQs. By selecting ciprofloxacin (Cip) as a typical model of FQs, the designed HVC sensing strategy has a wide linear correlation in the Cip concentration range of 20.0–2000.0 nM and a low detection limit of 8.3 nM after optimizing some experimental conditions, and the similar results were demonstrated by other FQs including enrofloxacin and levofloxacin, thus showing great potential applications for the FQs detection.