Kinetic Validation by MATLAB Simulation of the Ni(III)-HmP Decomposition Step in Nickel-Mediated Histamine Oxidation: Comparison with Thin-Layer Voltammetry

The complexation constant (K) governing the interaction between histamine (Hm) and nickel ions is a critical parameter for developing electrochemical biosensors for food safety monitoring. For the equilibrium $\text{Ni}{\left(\text{OH}\right)}_2+\text{Hm}？\text{HmNi}\left(\text{II}\right)+2{\text{OH}}^{？}$ , a mass-balance estimate based on our earlier work $K？\approx ？2.5\times {10}^6$ [1] confirms a strong Hm-Ni(II) affinity; this value is not re-derived here but is used as established context. The specific contribution of the present study concerns the kinetics of the subsequent chemical step (decomposition of the Ni(III)-HmP adduct). Thin-layer voltammetry gives $k=\left(2\pm 1\right)\times {10}^{？6}{\text{？s}}^{？1}$ [1], while an independent MATLAB kinetic simulation (ODE45) of the coupled electrochemical-chemical process reproduces this value with $\text{ksim}=2.8\times {10}^{？6}$ , in agreement with the experimental rate constant within its reported uncertainty ($k=\left(2\pm 1\right)\times {10}^{？6}{\text{？s}}^{？1}$