Sh. Liu et al., VOLTAMMETRIC DETERMINATION OF SEQUENCE-SPECIFIC DNA BY ELECTROACTIVE INTERCALATOR ON GRAPHITE ELECTRODE, Analytica chimica acta, 335(3), 1996, pp. 239-243
A synthesized 24-mer single-stranded deoxyribonucleic acid (ssDNA) was
covalently immobilized onto a chemically-modified graphite electrode
with surface-bound primary amino groups, using water-soluble 1-ethyl-3
-(3-dimethylaminopropyl)-carbodiimide (EDC). The immobilized ssDNA was
hybridized with various concentrations of complementary DNA (cDNA) in
hybridization buffer solution containing ethidium bromide (EB). The d
sDNA/EB system was formed on the electrode surface. The anodic waves o
f the EB bound to the double-stranded DNA (dsDNA) in cyclic voltammetr
y were used for the determination of cDNA. The anodic peak currents (i
(pa)) of EB were linearly related to the concentrations of cDNA betwee
n 1 x 10(-4) mg ml(-1) and 1 x 10(-6) mg ml(-1). The detection limit w
as about 2 x 10(-7) mg ml(-1).