Synthesis and Characterization of Carbon–Alumina Electrodes for Simultaneous Detection of Aclonifen and Methyl Parathion

Alumina–based electrodes offer promising possibilities for sensitive electrochemical sensors, but their development is hindered by poor intrinsic electrical conductivity. To overcome this limitation, new carbon-alumina composites were synthesized via a sol-gel method using two distinct calcination approaches: conventional and flash-calcination. The structural and textural properties of pure alumina samples were affected by the calcination approach. The introduction of carbon reduced the crystallite size and increased the specific micropore surface area and total pore volume of the samples. Electrochemical characterization by cyclic voltammetry and electrochemical impedance spectroscopy revealed that the optimal sample was obtained by conventional calcination for 30 min. This approach produced optimal structural integration, with a well-connected network and superior charge-transfer kinetics. The optimized carbon-alumina composite demonstrated excellent performance for the simultaneous electrochemical detection of methyl parathion and aclonifen by utilizing intermediate reduction products. The resulting sensor achieved wide linear ranges (0.5 to 20 µM) alongside low detection limits of 0.08 µM for methyl parathion and 0.14 µM for aclonifen, establishing these composites as effective materials for sensing applications.