Preliminary Study of Electrochemical Behavior of Ketjen Black Modified Glassy Carbon Electrode (GCE) in Dopamine Solution

Modification of a glassy carbon electrode (GCE) using Ketjen black has been done. Ketjen black (KB) was attached to the GCE surface employing the drop-casting method with the support of sodium cholate as a surfactant. The measurement was performed using cyclic voltammetry. The preliminary study of the electrochemical behavior of KB-modified GCE was observed using 1 mM dopamine in acetate buffer pH 4 as a supporting electrolyte. The result shows that the anodic peak current of a modified GCE is higher than that of a GCE without modification. It indicates that KB gives a synergy effect for GCE to increase the anodic peak current of dopamine measurement. In selectivity studies, modification of a GCE using KB can improve the selectivity of the sensor. An unmodified GCE is selective for dopamine, uric acid, ascorbic acid, and glucose. After modification of the surface, a GCE is only selective for dopamine. In electrochemical behavior study, five repetitions of measurement resulted in a decrease in the anodic peak current. It indicates that the oxidation product of dopamine molecules is attached strongly to the surface of the KBmodified GCE surface during voltametric measurement causing a decrease in the anodic peak current.