Electrochemical sensor based on ZIF-67/MWCNTs nanocomposite for 4-aminophenol determination in water samples

The modification of a screen-printed graphite electrode (SPGE) with a zeolitic imidazolate framework-67/multi-walled carbon nanotubes (ZIF-67/MWCNTs) is described for the sensitive detection of 4-aminophenol (4-AP). The ZIF-67/MWCNTs nanocomposite was prepared by a facile synthesis method and was characterized by fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) analysis, field-emission scanning electron microscopy (FE-SEM), and energy dispersive X-ray spectroscopy (EDS). The synergistic effects between ZIF-67 and MWCNTs resulted in significant electrocatalysis of the redox process of 4-AP on the modified SPGE. A quantitative detection of 4-AP was achieved with a linear concentration range of 0.01–675.0 µM, a limit of detection (LOD) of 0.008 ± 0.0001 µM and a high sensitivity of 0.0718 µA/µM. The ZIF-67/MWCNTs modified SPGE sensor demonstrated good stability, repeatability, and reproducibility for the detection of 4-AP. Moreover, the assessment of the interference effect of some species on the detection of the 4-AP revealed that the designed sensor possesses good selectivity towards the 4-AP. The ZIF-67/MWCNTs modified SPGE sensor was successfully used for the determination of 4-AP in water samples with a relative standard deviation (RSD) of 3.6% and recoveries between 97.1% and 104.4%.