Non-enzymatic disposable electrochemical sensors based on CuO/Co3O4@MWCNTs nanocomposite modified screen-printed electrode for the direct determination of urea

Abstract

A new electrochemical impedimetric sensor for direct detection of urea was designed and fabricated using nanostructured screen-printed electrodes (SPEs) modified with CuO/Co3O4 @MWCNTs. A facile and simple hydrothermal method was achieved for the chemical synthesis of the CuO/Co3O4 nanocomposite followed by the integration of MWCNTs to be the final platform of the urea sensor. A full physical and chemical characterization for the prepared nanomaterials were performed including Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), contact angle, scanning electron microscope (SEM) and transmission electron microscopy (TEM). Additionally, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to study the electrochemical properties the modified electrodes with the nanomaterials at different composition ratios of the CuO/Co3O4 or MWCNTs. The impedimetric measurements were optimized to reach a picomolar sensitivity and high selectivity for urea detection. From the calibration curve, the linear concentration range of 10−12–10−2 M was obtained with the regression coefficient (R2) of 0.9961 and lower detection limit of 0.223 pM (S/N = 5). The proposed sensor has been used for urea analysis in real samples. Thus, the newly developed non-enzymatic sensor represents a considerable advancement in the field for urea detection, owing to the simplicity, portability, and low cost-sensor fabrication.

Urea Electrooxidation in Alkaline Environment: Fundamentals and Applications

“…If the electrolyte keeps neutral statues, urea was decomposed mainly to nitrite and nitrate ions and resulted in CO 2 generation [1a] . In addition, the normal urea concentration is 2.5–7.5 mM in healthy adult serum [4] . Urea biosensors based on electrochemical UOR can achieve rapid determination toward urea with good electrochemical response and selectivity [5] …”

“…[1a] In addition, the normal urea concentration is 2.5-7.5 mM in healthy adult serum. [4] Urea biosensors based on electrochemical UOR can achieve rapid determination toward urea with good electrochemical response and selectivity. [5] Electrochemical systems have been utilized in various scenarios with different configurations and purposes, resulting in varying urea conversion behaviors.…”

Design of metal oxide nanoparticles‐embedded polymeric nanocomposites for hydrogen peroxide chronoamperometric sensor

“…Additional electrochemical characteristics, such as reversibility and electro‐catalytic activity can be explained by estimating the peak potential and the half‐peak potential ( E 1/2 ) 45 . The CuO, MnO 2 , CdO, and SeO 2 embedded poly(MMA/DMAEMA/AA) nanocomposites displayed two oxidation/reduction peaks with E 1/2 values of 0.08, 0.117, 0.11, and 0.05 V, respectively.…”

Structural, dielectric, and electrochemical properties of pear-shaped CexLi2Zn0.5Mn0.5Ti3−xO8 supercapacitor: XRD and dielectric calculation

“…By electrochemical system, chemical and physical processes could be characterized and studied using cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques (table 2). Thus, the stability, performance and charge transport properties of any suggested materials could be monitoring [35][36][37][38].…”