Simultaneous determination of guanine and adenine contents in DNA, RNA and synthetic oligonucleotides using a chemically modified electrode

Abstract

Simultaneous determination of guanine and adenine contents in DNA, RNA and synthetic oligonucleotides an a Nafion-ruthenium oxide pyrochlore modified electrode is described. This chemically modified electrode shows very pronounced electrocatalytic effects towards the oxidation of guanine and adenine. The experimental parameters for individual determinations of guanine and adenine on the modified electrode were first optimised. Excellent detection limits (S/N = 3) of 0.86 ng ml(-1) (5.7 nM) and 2.7 ng ml(-1) (20 nM) for guanine and adenine, respectively, were obtained. Simultaneous determination of guanine and adenine in a mixture was also optimised. The denatured calf thymus DNA and yeast RNA showed oxidation peaks corresponding to guanine and adenine with a linear calibration line up to 5 mu g ml(-1) in pH 4.0 phosphate buffer. The detection limit estimated for these nucleic acids were 11.5 ng ml(-1) and 37.7 ng ml(-1) for guanine and adenine, respectively. The new method provides an alternative to estimate the guanine and adenine contents more selectively and sensitively than currently applied techniques

TiO2-graphene nanocomposite for electrochemical sensing of adenine and guanine

“…Therefore, the guanine and adenine could be determined simultaneously from a mixture in large concentration domains by the proposed method. The linear detection range for both A and G is 0.5-200 M, which is much wider than the previously reported electrochemical sensors [34][35][36][37][38][39]. The detection limit (S/N = 3) for A and G was calculated to be 0.10 M and 0.15 M, respectively.…”

“…6). It has also been observed in earlier reports that the calibration curve of A and G detection usually divided into two linear regions [34,37]. The first linear region in the calibration curve can be ascribed to an absorption process of A or G on the modified electrode surface, and the second linear region may be attributed a diffusion process on the monolayer-covered surface [37].…”

“…However, adenine and guanine exhibit slow direct electron transfer and irreversible absorption on the electrode surface, which lead to low sensitivity for DNA detection. Over the past years, considerable efforts have been paid on the development of chemical modified electrodes to improve the electrochemical sensing performance for guanine and adenine [31][32][33][34][35][36][37][38][39]. Most recently, Dong and coworkers revealed that the free base of DNA have enhanced electrochemical reactivity at the graphene modified glassy carbon electrode [10].…”

Enhancement of Anodic Response for DMSO at Ruthenium Oxide Film Electrodes as a Result of Doping with Iron(III)

“…Cox et al demonstrated that ruthenium oxide films containing cyanide with ruthenium in two valences, when coated on glassy carbon electrodes, would yield convective-diffusional controlled anodic response for cysteine and glutathione [13]. Zen et al reported on the electrocatalytic properties of Nafion/ruthenium oxide pyrochlore and Nafion/lead ruthenate pyrochlore chemically modified electrodes with respect to oxidation of various compounds including cysteine [14,15], guanine and adenine [16] hydrazine [17], hypoxanthine [18], and dopamine [19]. They reported a detection limit for cysteine of 1.9 mM using square-wave voltammetry and 1.70 nM using flow injection analysis [14].…”

Carbon materials for the electrooxidation of nucleobases, nucleosides and nucleotides toward cytosine methylation detection: a review

“…105 With regard to the strong adsorption of molecules on the electrode surface, it is interesting to highlight that while that can provide high sensitivity, at the same time that can result in the formation of insulating layers on the surface, causing electrode fouling and non-lineal calibration curves. 107 On the other hand, it can be stated that the oxidative processes of the nucleobases are under diffusion control, being the peak currents directly proportional to the square root of the scan rate (ν 1/2 ) in the scan rate range from 25 to 300 mVs -1 , 105 as well as for dGMP (deoxyguanosine monophosphate), tRNA (transfer RNA), ssDNA and dsDNA. 108 As previously mentioned, the theoretical value of -60 mV pH 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 protons.…”