<![CDATA[Chitosan-based nanocomposite coatings are promising low-cost electrochemical materials, but the relationship between interfacial structure and voltammetric performance remains insufficiently understood. This study investigated the cyclic voltammetric behavior, reproducibility, and cycling stability of a copper-supported crosslinked chitosan–glutaraldehyde/zinc oxide coating. Structural and electrochemical characterization was performed using Fourier transform infrared spectroscopy, scanning electron microscopy/energy-dispersive X-ray spectroscopy, and cyclic voltammetry in 0.1 M phosphate-buffered saline and 0.01 M K₃[Fe(CN)₆]/0.10 M KCl. The coating showed Schiff-base crosslinking, Zn-related interactions, compact morphology, good attachment to copper, and distributed Zn-containing domains without obvious large-scale agglomeration. Electrochemically, the coating exhibited quasi-reversible behavior in both media. Ferricyanide produced sharper redox features, current ratios closer to unity, and stronger anodic linearity with the square root of scan rate than phosphate-buffered saline. The apparent diffusion coefficient estimated from the ferricyanide anodic response was on the order of 10⁻⁵–10⁻⁶ cm² s⁻¹. Reproducibility across ten independently prepared electrodes was acceptable, with lower variability in ferricyanide than in phosphate-buffered saline, and the voltammetric profile was retained over 15 cycles. These results demonstrate a stable and reasonably reproducible electrochemical interface with potential for future sensing applications.]]>
