Voltammetric determination of mifepristone at a DNA-modified carbon paste electrode

A new strategy for the preparation of a DNA-modified carbon paste electrode is developed. It is found that the anodic response of mifepristone is grea tly enhanced at the dsDNA-modified carbon paste electrode comparing with th at obtained at the bare electrode, while the response at a ssDNA-modified e lectrode is similar to bare electrode. So the dsDNA-modified electrode is e mployed as a sensitive biosensor for the detection of mifepristone. A linea r dependence of the peak currents on the concentration is observed in the r ange 2.0 x 10(-7) similar to2.0 x 10(-6) mol/L, with a detection limit of 1 .0 x 10(-7) mol/L. The relative standard deviation is 4.3% for six successi ve determinations of 1.0 x 10(-6) mol/L mifepristone. The determination of mifepristone tablets is carried out and satisfactory results are obtained.