Europium-(7-carboxymethoxy-4-methyl coumarin)2 Complex based Electrochemical Probe for DNA based on the Interaction between Them

The interaction of Eu(III) ion with 7-carboxymethoxy-4-methylcoumarin (CMMC) has been investigated using the potentiometric method in the ethanol-water mixture solvent (0.15 volume fraction). The formation of the different binary, ternary complexes is confirmed by the corresponding pH-potentiometric curves. SUPERQUAD computer program has been used for the refinement of all the calculated constants in our present study. Electroanalytical techniques have been used to confirm the formation of different binary and ternary complexes under investigation. The binding constant of the ternary complex Eu(III)-CMMC-DNA calculated by cyclic voltammetry (CV) and differential pulse (DP) was found to be 1.8 and 2.5x 105 M-1 in Tris-HCl, respectively. The changes in the current intensity have been used for the quantitative determination of DNA over a linear concentration range with LOD of 1.0-1.3 µg/ ml in 0.1 M Tris-HCl buffer.