DNA-Modified Electrodes. Part 5. Electrochemical Behavior of Co2+ at DNA-Modified Gold Electrodes in the Presence of 2,2′-Bipyridyl

摘要

The electrochemical behavior of Co2+, whose response is abnormally enhanced at DNA-modified gold electrodes in the presence of 2,2′-bipyridyl, was found. After it forms an adduct with Co2+, excess 2,2′-bipyridyl can enhance the electro-chemical response of this adduct at DNA-modified gold electrodes by synergism. ssDNA-modified gold electrodes that are highly sensitive to Co2+ were utilized to determine trace Co2+ in the presence of 2,2′-bipyridyl by cyclic voltammetry. It was found that the peak currents for cobalt increase linearly over the concentration range of 1.0×10-7 - 1.1×10-6 mol/l with a detection limit of 4.0×10-8 mol/l. For seven preconcentration/voltammetric detection/renewal cyclic experiments with 1.0×10-7 mol/l and 1.0×10-6 mol/l Co2+ solutions, relative standard deviations of 2.7% and 1.9% were found, respectively, indicating that the DNA-modified gold electrodes were stable and repeatable.