Unveiling the Sensing Capabilities of Multi-Walled Carbon Nanotubes for Urea Detection through Optical and Electrical Characterization

Detecting the nitrogen content present in urea is of utmost importance in determining its suitability for agricultural applications. This specific research paper explores a method that employs Multi-Walled Carbon Nanotubes (MWCNT) as the sensing material. The study revealed promising results, showcasing that the MWCNT-based sensor achieved its peak sensitivity, detecting urea concentrations with good precision. Specifically, it demonstrated a maximum sensitivity of 0.49% at a urea concentration of $\mathbf{1 0 ~ m M}$. Moreover, the sensor exhibited impressive sensitivity, with a rapid response time of 46 seconds and an efficient recovery time of just above 7 minutes. The sensing mechanism was initially confirmed through analytical techniques such as Fourier Transform Infrared Spectroscopy (FTIR). By observing the change in intensity of the CO2 signal upon exposure to urea solution, the involvement of oxygen ions in the sensing process was validated. Furthermore, the confirmation of this mechanism was reinforced through detailed electrical characterization. Overall, the development of this sensing film represents a significant advancement in the field of urea detection as it offers a cost-effective solution that is non-enzymatic in nature, yet possesses good sensitivity. This breakthrough has the potential to greatly benefit agricultural practices by providing farmers and researchers with a reliable tool for assessing the quality of urea fertilizers efficiently and accurately.