Mg2+-Selective Electrode Comprising Double-Helical DNA as Receptive Entity

Abstract

Cyclic voltammograms of ferrocyanide/ferricyanide redox couple with a DNA-immobilized electrode gave the peak currents due to the reversible electrode reaction, which were significantly enhanced on adding Mg²⁺. The electrode responded also to Ca²⁺ and Ba²⁺, although the onset concentrations of the electrode response were 50-times larger than that for Mg²⁺. The selectivity in the order of Mg²⁺ > Ca²⁺, Ba²⁺ >> Na⁺, K⁺ seems consistent with the binding affinity of the metal ions with double-helical DNA.