Catechol (CC) is classified as a human carcinogen and environmental contaminant because of its high toxicity and low degradability. A pre-proof paper from the journal Food Chemistry focuses on the development of metal-organic framework (MOF) based nanocomposites (NCs) as a novel electrochemical sensing technology for catechol detection.
Study: Engineering MOFs derived metal oxide nanohybrids: Towards electrochemical sensing of catechol in tea samples. Image Credit: Zadorozhnyi Viktor/Shutterstock.com
Catechol (CC) is dihydroxy benzene found in many natural food sources, including tea, vegetables, tobacco, fruits, and many other plants. For humans, a deadly dose of CC ranges from 50 to 500 mg/kg, or one tablespoon for a 70 kg individual.
Even in little dosages, Catechol may induce central nervous system (CNS) damage and a persistent increase in blood pressure. Therefore, it is necessary to develop simple, dependable, and sensitive detection techniques.
Limitations of Current Catechol Detection Methods
Many analytical approaches such as gas chromatography, surface plasmon resonance, high-performance liquid chromatography, and spectrophotometry are utilized for catechol detection. However, these techniques have several limitations such as low selectivity, difficult operation, and high sample pre-treatment costs, restricting their practical implementation.
Electrochemical sensing is an emerging detection method in investigating ecological and physiological materials because of its strong selectivity, sensitivity, rapid analytical response, simple equipment, and cost-effectiveness. However, sensing efficacy is highly dependent on the chemistry of the electrode substance, resulting in inconsistent analyses.
Metal-Organic Frameworks (MOFs) for CC Detection
Researchers are now working on establishing robust analytical methodologies for detecting phenolic chemicals like Catechol in industrial and ecological samples utilizing metal-organic frameworks (MOFs)-based detectors. The MOFs are used as precursors in the thermolysis production of a variety of valuable materials like metallic oxides and nanocomposites.
MOFs can be merged with other beneficial and highly conducting materials such as copper and its derivatives to overcome their weak electrical properties.
Compared to single non-metal and metal oxide materials, the mixture of mixed transition metal oxides (MTMOs) and MOFs can enhance the overall conductance of the sensor. This is because MTMOs play an important role in increasing the electrocatalytic behavior of produced materials.
Nickel oxide (NiO) is a desirable transition metal oxide (TMO) in this context because of its remarkable antiferromagnetic characteristics, high catalytic efficiency, high-temperature resistance, excellent chemical durability, strong conductance, and superb dynamic scattering.
A Novel MOF-based Electrochemical Sensor
In this study, the researchers developed a novel electrochemical sensor based on combining copper, nickel oxide, and MOFs (Cu-MOF/CuO/NiO) using a simple hydrothermal method.
Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were carried out to characterize the as-fabricated Cu-MOF/CuO/NiO electrochemical sensor.
The developed electrochemical sensor was used to detect Catechol from two varieties of tea, namely black and green tea, to assess the practicability of the Cu-MOF/CuO/NiO-based sensing medium.
Highlights and Key Developments of the Study
In this research, a novel electrochemical sensor comprising Cu-MOF/CuO/NiO nanocomposites was manufactured via a reliable hydrothermal technique for the extremely selective, accurate, and exact detection of Catechol in tea samples.
This is one of the first studies to describe the synthesis and implementation of a copper-based metal-organic framework (Cu-MOF) as a sacrificial template for the construction of electrochemical sensors.
The Cu-MOF/CuO/NiO electrochemical sensor exhibits exceptional electrochemical performance due to appealing properties such as great catalytic efficiency, permeability, high conductance, and the synergistic effect of doped components.
Compared to previously reported nanomaterials-based catechol biosensors, the novel electrochemical sensors developed in this study demonstrated a low value of the limit of detection (LOD) with appropriate analytical characteristics such as responsiveness, repeatability, and a wide linear intensity range (0.01 - 22 M).
As a proof of concept, the proposed electrochemical sensor has been successfully employed for rapid and accurate catechol identification, revealing its optimistic broad range of prospective applications in regular tea sample analysis.
Using this manufacturing technique, the applications of MOF-derived electrochemical sensors can be expanded to design various multi-metal oxides nanocomposites for use in photocatalysis, sensing systems, and environmental monitoring.
Iftikhar, T. et al. (2022). Engineering MOFs derived metal oxide nanohybrids: Towards electrochemical sensing of catechol in tea samples. Food Chemistry. Available at: https://www.sciencedirect.com/science/article/pii/S0308814622016041?via%3Dihub