Screen-printed electrode system based on carbon black/copper-organic framework hybrid nanocomposites for the electrochemical detection of nitrite

Abstract

Screen-printed electrodes have recently received increasing attention in many electrochemical sensing applications due to their compact size, which allows for on-site detection of contaminants. This research aimed to develop an electrochemical sensor for detecting nitrite in wastewater samples by immobilizing carbon black/copper metal-organic framework (CB/Cu-MOF) nanocomposites on the surface of a screen-printed carbon electrode (SPCE). The surface morphology, surface structure and thermal properties of the synthesized materials were investigated using scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffractometer, Raman spectroscopy, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. Additionally, the electrochemical properties of the electrodes were studied using cyclic voltammetry, electrochemical impedance spectroscopy, and linear sweep voltammetry (LSV). The CB/Cu-MOF/SPCE-based nano-sensor exhibited a lower limit of detection and limit of quantification of 0.084 µmol L−1 (S/N = 3) and 0.28 µmol L−1 (S/N = 10), respectively. A dynamic linear range concentration of 1–200 µmol L−1 was also obtained towards the detection of the nitrite using LSV technique. The CB/Cu-MOF nanocomposite-based SPCE showed excellent repeatability (RSD = 0.150%) and reproducibility (RSD = 0.12%). The electrochemical detection feasibility of the CB/Cu-MOF/SPCE towards the detection of nitrite was successfully applied in wastewater samples within an acceptable range of recoveries of 100.90–103.40%. Hence, the introduced CB/Cu-MOF/SPCE nanosensor showed an increased potential for monitoring a wide range of concentration for nitrite in aquatic samples.