Electrochemical Investigation of DNA Interaction with Melamine and its Related Compounds (MARCs)

The interaction of melamine (MM) and its related compounds (MARCs), i.e. Ammeline (AMN), Ammelide (AMD), Cyanuric acid (CA) with native Herring Sperm DNA (HS-DNA) has been investigated by cyclic voltammetric studies at glassy carbon electrode (GCE) in phosphate buffer (PBS at pH 7.0). It was observed that the electrochemical processes of the 4 MARCs at a bare GCE were quasireversible. By adding HS-DNA into the MARCs solutions, a decrease in reduction peak current of MARCs with a slight negative shift in peak potential values was observed. The reduction peak current (Ipc) of any of the MARCs, either in absence or presence of HS-DNA, varied linearly with scan rate (v) rather than v1/2, which indicated that the electrode process was controlled by adsorption step. The number of electrons transferred per molecule (n) of MM or the other three MARCs was calculated to be ca. 2. Electrochemical parameters (charge transfer coefficient α and the standard rate constant ks) of free MARCs and binding compounds were obtained according to Laviron theory. The interactions between MARCs and HS-DNA were presumed in groove mode with the interaction constants to be 104~105 L⋅mol-1.