A novel electrochemical sensor based on CuBTC metal–organic framework decorated with carbon nanotube for highly sensitive detection of enrofloxacin in water samples

In this study, a novel electrochemical sensor employing a synthesized CuBTC metal–organic framework modified with carbon nanotubes was developed for the quantitative detection of enrofloxacin using an adsorptive stripping square wave voltammetric method. Surface and structure characteristics of the composite material and the modified electrode were analyzed using modern techniques such as Scanning Electron Microscopy, X-ray Diffraction, Fourier Transform Infrared Spectroscopy, X-ray Photoelectron Spectroscopy, Thermogravimetric Analysis, and Energy Dispersive X-ray Spectroscopy. The synergy between CuBTC and CNT significantly enhanced the adsorptive stripping voltammetric signal of ENR on the developed electrode, resulting in a peak current 12.5 times greater than that observed on an unmodified electrode. Additionally, the electrochemical performance of the electrode confirmed its enhanced electroconductivity and its effectiveness as an electrocatalyst in the oxidation of ENR. Under optimized analytical conditions, the electrode exhibited excellent performance within the ENR concentration range of 0.01 μM to 12 μM, corresponding to three linear ranges with different accumulation times. The detection limit of the method achieved for ENR detection was 0.003 μM. Furthermore, the proposed sensor demonstrated excellent reproducibility, selectivity, and long-term stability, enabling precise ENR determination in various water samples and a simulated urine with satisfactory results (recoveries ranging from 98 to 101.5% and relative standard deviations between 2.07% and 6.42%). Graphical abstract