Biology Reference
In-Depth Information
ionswasdescribed[71].Theproposedelectrochemicalmethodwas
used either for the detection of different ODN lengths containing
onlyadenineunits(withthenumberofadenineunitswithin10and
80) or for the determination of the number of purine units within
the30-merODNscontainingarandomsequencesegmentsinvolving
both the purine and pyrimidine units. A good correlation between
the content of purine units with the whole length of different
30-mer ODNs and the current intensity of the electrochemically
accumulated complexes was found. The sensitive detection of
different ODNs containing the purine units in their chains in the
presence of copper can also be performed at other amalgam
alloys, for example, the platinum amalgam-alloy electrode, copper
amalgam-alloy electrode, and silver amalgam-alloy electrode [71].
Copper-enhanced label-free anodic stripping detection of guanine
and adenine bases in acid-hydrolyzed DNA at anodically oxidized
boron-doped diamond electrode (BDDE) has been published [72].
The BDDE was successfully applied in a three-electrode micro-cell
in which a 50
μ
L drop of the analyte solution can be e
ciently
stirred during the accumulation step by the streaming of an inert
gas. Accelerated mass transport due to the solution motion in
the presence of copper resulted in enhancement of the guanine
oxidation signal, allowing easy detection of 25 fmol of ODNs. It
was also shown that the edge-plane pyrolytic graphite electrode,
whose surface was mechanically roughened, enables voltammetric
analysisofpurinenucleobases,acid-hydrolyzedsyntheticODNs,and
a nonhydrolyzed plasmid DNA [73]. In the presence of copper ions,
theycausedastrongenhancementofthepurineoxidationresponses
at fine-polished carbon electrodes.
11.6 Conclusions
EVLS is an unconventional, perspective electrochemical method
capable of eliminating or conserving selected partial currents
(diffusion current, charging current, kinetic current, etc.) from the
total voltammetric current and thereby enhancing the sensitivity
and improving the resolution of the measured voltammetric signals
[5, 6]. EVLS in combination with the adsorptive stripping or
adsorptive transfer stripping (AdS or AdTS) techniques has been
