Resolution of Overlapped Reduction Signals in Short Hetero‐oligonucleotides by Elimination Voltammetry

Abstract

The resolution of overlapped reduction voltammetric signals of adenine (A) and cytosine (C) residues in short synthetic hetero-oligodeoxynucleotides (ODNs) with different sequences of A and C, but with the same ratio (A/C ¼ 1/2), was carried out by elimination voltammetry with linear scan (EVLS). The EVLS, as a mathematical transformation of voltammetric total currents measured at different scan rates, is capable to yield very sensitive resolution of potentially closed signals, which cannot be separated by common electrochemical methods. The best resolution of A and C signals was observed when the EVLS function eliminating the charging and kinetic currents (I c , I k ) and conserving the diffusion current (I d ) was combined with adsorption stripping technique (AdS). The resulting peak-counterpeak signal made it possible not only to separate the responses of A and C residues, but also to follow the dynamics of adsorption processes on mercury electrode surfaces. Together with the effect of the accumulation time on peak-counterpeak signal, the effect of pH and temperature on this signal was studied. The relation between elimination signals and the structure changes of ODNs was discussed.

Double Elimination Voltammetry of Short Oligonucleotides

“…It is known that organized structures of Cs can be formed after their partial protonization. This phenomenon can result in assembling of Cs and As in one ODN molecule via intramolecular association [16]. This is in good agreement with findings by NMR method concerning the behavior of oligomers containing section of Cs in solution [18].…”

“…It is noteworthy that only for ODN H3 the slope S I is also 1, but only in the range of slow scan rates (1.563, 3.125, 6.25, 12.5, and 25 mV/s). In accordance with the previous paper we assume that kinetics of H3 connected with structural changes of its chain on HMDE takes place, and signals recorded at higher scan rates can be influenced by these surface reactions [16]. The effect of sequence of bases demonstrates also the change of E p as a function of scan rate (bottom part of Fig.…”

“…Based on the results obtained using E4 transformation the best resolution of fully overlapped A and C signals of ODNs H3 and partly of H4 occurred at pH 6.34 [16]. However, for all three ODNs the separation at this pH was successful when double EVLS was applied (Fig.…”

G-quadruplex-based structural transitions in 15-mer DNA oligonucleotides varying in lengths of internal oligo(dG) stretches detected by voltammetric techniques

“…Several papers have been devoted to hairpinforming ODNs [12] and studies focused on DNA-mediated charge transfer [13]. Results of some quite recent studies showed that the behavior of ODNs at the mercury and amalgam electrodes is strongly dependent on their nucleobase composition (especially when a specific nucleobase or nucleobase type strongly prevails) [14] and nucleotide sequence (especially when it is non-random) [12,[15][16][17][18]. Grich ODNs have recently been studied by voltammetric methods at a glassy-carbon electrode in combination with atomic-force microscopy [19][20][21].…”

Voltammetric Study of Aminopurines on Pencil Graphite Electrode in the Presence of Copper Ions

“…The shape of this signal was calculated theoretically and the theoretical ratio of peak to peak-counterpeak height corresponds to 0.4097 [29]. This fact initiated the application of the adsorptive transfer stripping (AdS) technique together with EVLS for the analysis of oligonucleotides, including hairpins [27,30,31]. It was found that AdS EVLS was able to separate overlapped voltammetric peaks and to indicate quickly the adsorbed state of depolarizers.…”