Additionally, the CV of CPZ was conducted for comparison to 2-CPTZ. As shown in Figure (a), six oxidation events were observed using a potential window up to 3.0 V. The first oxidation peak corresponds to the reversible process of redox species at an anodic potential of 0.595 V (Epa1) and a cathodic potential of 0.492 V (Epc1) (fast electron transfer, Figure ). The CV profile of CPZ is in accordance with the literature. This reversible redox reaction corresponds to the oxidation of CPZ to form radical cation CPZ •+ involving a one-electron process. The second to the sixth processes are irreversible behaviour and were observed at Epa1-6: 0.765, 1.172, 1.355, 1.909, and 2.113 mV vs Fc/Fc + , respectively. The irreversible process was confirmed swept up to 3.0 V for multiple scan analysis, indicating that after first scanning, the reaction generates new chemical species/intermediate species in the Ep2 (Figure ). Ep2 shifts to more positive potential from the first sweep 1.182 to the second sweep 1.240 V and to the third sweep 1.268 V. To determine whether the redox process during CPZ oxidation is controlled by adsorption or diffusion, a potential scan rate study was performed based on CV between 0.05 and 0.30 Vs -1 . Additionally, the slope of the plot of log Ep vs log scan rate shows that the oxidation process of CPZ is diffusion-controlled with a slope close to 0.5 (slope: 0.01404, Figure ; and the slope in the anodic peak current logarithm plot (log Ip) vs the potential scan rate logarithm (log v) shows that the process is controlled by mass transfer closer to the theoretical value of 0.5 (slope: 0.5212, Figure ). In concentration and scan rate studies, CPZ shows that increasing concentrations result in an increase in peak potential. This correlation is confirmed by plotting the peak of potential against concentration (weak correlation with the regression equation 0.8896, Figure ) and the concentration of the analyte affects the peak current in accordance with the Randles-Sevcik equation, indicating a diffusion-controlled redox process (Figure (b) and Table . In contrast to the scan rate study, the analysis shows the non-dependent on the scan rate with the regression equation 0.6521, Figure .