Simultaneous Detection Of Guanine Research Articles

Facile Synthesis of Cyclodextrin Functionalized Reduced Graphite Oxide with the Aid of Ionic Liquid for Simultaneous Determination of Guanine and Adenine

AbstractHere, a facile reduction approach for synthesis of β‐cyclodextrin functionalized reduced graphite oxide with the aid of ionic liquid (βCD/IRGO) was reported. This strategy relies on the simple mixing of pre‐pared aqueous βCD/GO with ionic liquid (IL) at high temperatures, which can bring about a well dispersed βCD/RGO in the utilized IL (βCD/IRGO) with a synchronous evaporation of water. The as‐prepared βCD/IRGO product can be stably re‐dispersed in water (up to 1.0 mg/mL) after washed and dried. And the presented βCD/IRGO composites possess high supramolecular recognition capability and good conductivity for realizing enhanced electrochemical response towards simultaneous detection of guanine and adenine compared with other βCD/carbon (RGO or carbon nanotube) based composites. In the presence of one of analysts, the linear response ranges is 0.03–10.0 μM for guanine and 0.02–7.0 μM for adenine, respectively, with detection limit of 0.01 μM for both guanine and adenine (S/N=3). This ease of making the βCD/IRGO composite will open up possibilities of its diversifier applications.

An Electrochemical Sensor Based on Gold Nanoparticles Incorporated in Mesoporous MFI Zeolite for Determination of Purine Bases in DNA

AbstractAn electrochemical sensor was developed based on gold nanoparticles incorporated in mesoporous MFI zeolite for the determination of purine bases. Au nanoparticles (AuNPs) were incorporated into the mesoporous MFI zeolite (AuNPs/m‐MFI) by post‐grafting reaction. The composite materials were characterized by transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS) and electrochemical methods. Au nanoparticles with a size of 5‐20 nm are uniformly dispersed in the pores of mesoporous MFI zeolite. And the morphology of MFI zeolite can be perfectly kept after pore expansion and Au nanoparticles incorporation. The electrocatalytic oxidation of purine bases (guanine and adenine in DNA) is investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The surface‐confined Au nanoparticles provide the good catalytic activity for oxidation of purine bases. The simultaneous detection of guanine and adenine can be achieved at AuNPs/m‐MFI composites modified glassy carbon electrode (GCE). The electrochemical sensor based on AuNPs/m‐MFI exhibits wide linear range of 0.5–500 μM and 0.8–500 μM with detection limit of 0.25 and 0.29 μM for guanine and adenine, respectively. Moreover, the electrochemical sensor is applied to evaluation of guanine and adenine in herring sperm DNA samples with satisfactory results.

A flow injection analysis coupled dual electrochemical detector for selective and simultaneous detection of guanine and adenine

Adenine (A) and guanine (G), important bases of nucleic acids, are often analyzed by separation coupled spectroscopic detection methods. Herein, we are demonstrated a new flow-injection analysis (FIA) coupled dual electrochemical detector (DECD), where a chitosan-carbon nanofiber (Chit-CNF) modified glassy carbon electrode prepared by a simple technique and pH 7 phosphate buffer solution as a carrier system, for separation-less quantification of G and A. This method is highly selective and no interference by the presence of the other DNA bases (Thymine and Cytosine). The FIA-DECD was operated at two different operating potentials, E1=0.80V and E2=0.95V vs Ag/AgCl, where G and {G+A} get oxidized, respectively. Amount of A was calculated from the difference between the FIA current signals, measured at E20.95V and E10.80V. The GCE/Chit-CNF was characterized by cyclic voltammetry with potassium ferricyanide system and Raman spectroscopy. The modified electrode showed unique electron-transfer feature with metal like conductivity. Under an optimal condition, FIA-DECD showed linear calibration plots for G and A in a concentration range, 200 nM—50μM with current sensitivity values 13.83±0.48 and 4.84±0.11nA μM−1 respectively. Calculated detection limit (signal-to-noise ratio=3) values were 46.8nM and 73.8nM for G and A respectively. Applicability of the present technique was further demonstrated by detecting G and A in beef kidney sample and DNA hybridization process.

Simultaneous detection of guanine, adenine, thymine, and cytosine at polyaniline/MnO2 modified electrode

In this study, PANI/MnO2 nanocomposite was synthesized by the reaction of polyaniline (PANI) and KMnO4 in the aqueous medium. Material was characterized by X-ray diffraction, nitrogen sorption, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and FT-IR. PANI/MnO2 modified electrode was investigated in the simultaneous detection of all four DNA bases (guanine, adenine, thymine, and cytosine) using cyclic and differential pulse voltammetries. pH was optimized to obtain the best peak potential separation and response current. This enabled us for the simultaneous voltammetric determination of all four DNA bases at physiological condition (pH 7). PANI/MnO2 nanocomposite exhibited high-current sensitivity for these analytes compared to MnO2 and PANI modified electrodes. Under the optimum conditions, PANI/MnO2 exhibited low detection limit, good sensitivity, and wide linear range for the simultaneous detection of G, A, T, and C. Moreover, the proposed method was successfully applied in the determination of G, A, T, and C contents in a calf thymus DNA sample with satisfactory results. The reliability and stability of the modified electrode provide a good possibility for applying the technique in the routine analysis for a selected class of electroactive organic/bio-molecules.

Simultaneous detection of guanine and adenine in DNA and meat samples using graphitized mesoporous carbon modified electrode

A graphitized mesoporous carbon modified glassy carbon electrode (GCE/GMC) prepared by drop coating method without any pre-anodization of the underlying GCE or external binder/matrix, has been demonstrated for simultaneous electrochemical oxidation of guanine (G) and adenine (A) at oxidation potentials 0.60 and 0.85 V vs. Ag/AgCl, respectively, in the presence of thymine (T) by differential pulse voltammetric method in pH 7 phosphate buffer solution. Control voltammetric experiments with unmodified GCE, graphite nanopowder and multiwalled carbon nanotube modified electrodes yielded either feeble or with high-background current responses. Interestingly, the GCE/GMC showed highly efficient, stable and well-defined voltammetric signals. Thymine oxidation signal noticed discretely at 1.15 V vs. Ag/AgCl on the GCE/GMC was not influenced for the simultaneous determination of G and A. Constructed DPV calibration graphs were linear in the range of 25–200 and 25–150 μM, respectively, for the G and A. Corresponding detection limit (S/N = 3) values are 0.76 and 0.63 μM. Real sample analyses for the detection of G and A concentrations in calf-thymus DNA (detected [G]/[A] ratio = 0.82), beef brain and beef liver were successfully demonstrated with recovery values ~100 %.