Electrochemical release of ethidium into and fluorescence detection of DNA-ethidium complexes in the diffusion layer at a carbon paste electrode.
The electrochemically controlled release of the ethidium cation from the surface of carbon paste composite electrode was demonstrated using laser-induced fluorescence detection. The electrode contained an ethidium tetracyanoquinodimethane salt. The following experimental parameters were varied in order to optimize the fluorescence intensity: carbon paste composition, electrode potential, voltage pulse time, and laser power. In the presence of calf thymus DNA the fluorescence signal from the diffusion layer was linearly dependent on the logarithm of the DNA concentration over the range from 0.1 to 10(4) ppb.
Swaile
B A
BA
Department of Chemistry, University of Tennessee, Knoxville 37996.
Chambers
J Q
JQ
D002244:Carbon; D004247:DNA / Q000032:analysis*; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004996:Ethidium; D005453:Fluorescence; D007700:Kinetics; D007834:Lasers
D002244:Carbon; D004247:DNA; D004996:Ethidium