Stripping voltammetric determination of purine bases inthe presence of copper ions at mercury, amalgam, orcarbon-based electrodes has recently been utilized inanalysis of DNA or synthetic oligodeoxynucleotides(ODNs). Here we report on copper-enhanced label-freeanodic stripping detection of guanine and adenine basesin acid-hydrolyzed DNA at anodically oxidized boron-doped diamond electrode (AO-BDDE). The AO-BDDEwas successfully applied in a three-electrode microcell inwhich an ~50
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L drop of the analyte solution can beefficiently stirred during the accumulation step by streaming of an inert gas. Accelerated mass transport due to thesolution motion in the presence of copper resulted inenhancement of the guanine oxidation signal by about 2orders of magnitude (compared to accumulation of theanalyte from still solution not containing copper), allowingan easy detection of ~25 fmol of the ODNs. The proposedtechnique is shown to be suitable for a determination ofpurine (particularly guanine) content in DNA samples.Applications of the technique in magnetic bead-basedDNA assays (such as hybridization with DNA sequencesexhibiting asymmetrical distribution of purine/pyrimidinenucleotides between the complementary strands or monitoring of amplification of specific DNA fragments in aduplex polymerase chain reaction) are demonstrated.