Voltammetric study of the interaction of lomefloxacin (LMF)-Mg(II) complex with DNA and its analytical application

The voltammetric behavior of the LMF-Mg(II) complex with DNA at a mercury electrode is reported for the first time. In NH3-NH4Cl buffer (pH = 9.10), the adsorption phenomena of the LMF-Mg(II) complex were observed by linear sweep voltammetry. The mechanism of the electrode reaction was found to be a reduction of LMF in the complex, and the composition of the LMF-Mg(II) complex is 2:1. In the presence of calf thymus DNA (ctDNA), the peak current of LMF-Mg(II) complex decreased considerably, and a new well-defined adsorptive reduction peak appeared at -1.63 V (vs. SCE). The electrochemical kinetic parameters and the binding number of LMF-Mg(II) with ctDNA were also obtained. Moreover, the new peak currents of LMF-Mg(II)-DNA system increased linearly correlated to the concentration of DNA in the 4.00 x 10(-7) - 2.60 x 10(-6) g ml(-1) range when the concentrations of LMF-Mg(II) complex was fixed at 5.00 x 10(-6) mol l(-1), with the detection limits of 2.33 x 10(-7) g ml(-1). An electrostatic interaction was suggested by electrochemical method. (C) 2003 Elsevier B.V. All rights reserved.