Catalytic Voltammetric Determination of Cladribine in Biological Samples

et al. 2005

Anal. Chem.

Self Cite

The generation of a new electrocatalytic system for NADH after oxidizing flavin adenine dinucleotide (FAD) is shown. The oxidation is performed in alkaline medium until +1.4 V (Ag/AgCl) at graphite electrodes. The catalytic activity is ascribed to the electrooxidized moiety of FAD and not to quinone surface groups. A comparison between this catalyst and that attributed to poly(FAD) (Karyakin, A. A.; Ivanova Y. N.; Revunova, K. V.; Karyakina, E. E. Anal. Chem. 2004, 76, 2004-2009.) is presented. It is concluded that the surface quinone groups generated during the strong anodization of the electrode in acidic medium at 2-2.5 V and not the poly(FAD) are responsible for the catalytic activity described in the above mentioned work.

Section: Resultssupporting

confidence: 91%

Flavin Adenine Dinucleotide As Precursor for NADH Electrocatalyst

de‐los‐Santos‐Álvarez

de-los-Santos-Álvarez

et al. 2005

Anal. Chem.

Self Cite

“…The amount of catalyst sharply decreases when the scan rate increases. This trend was also observed for other adenine nucleotides (AMP, ADP and ATP) and was just the opposite for adenine nucleosides (SAMe [25], cladribine [26] and fludarabine [27]), suggesting the relevant contribution of phosphate groups to the stabilization of the catalytic species. N9-substituent in adenine moiety was previously shown to be an essential requirement to observe any catalytic effect attributed to oxidized adenine derivatives.…”

supporting

confidence: 55%

Electrochemical and Catalytic Properties of the Adenine Coenzymes FAD and Coenzyme A on Pyrolytic Graphite Electrodes

de‐los‐Santos‐Álvarez

Miranda‐Ordieres

et al. 2005

Electroanalysis

Self Cite

Redox properties of two coenzymes, flavin adenine dinucleotide (FAD) and coenzyme A (CoA) are studied on pyrolytic graphite electrodes. Both of them exhibit an oxidation process at about 1.2 V in pH 9, associated with the oxidation of their adenine moiety. The resulting adsorbed oxidation products have a common structure, an electroactive quinone-imine that acts as efficient catalyst of the oxidation of NADH at low potentials. The influence of the structure on their electrochemical features in comparison with other adenine derivatives is studied. Finally, a modified electrode prepared with the oxidation product of CoA was used to determine NADH in a wide linear range (1 Â 10 À8 -2.43 Â 10 À5 M) with a detection limit of 3 nM.

“…In this instance hybridisation and interaction between DNA and the indicator, phenoxazine BCB, is accomplished in solution and the resulting mixture is evaporated to dryness on a graphite electrode. The intercalated BCB can catalyse NADH oxidation, enabling distinct discrimination between dsDNA and ssDNA, because when no hybrids are present the catalytic current is almost negligible [140,141].…”

Section: Methods Based On Hybridisation Indicatorsmentioning

confidence: 99%

Current strategies for electrochemical detection of DNA with solid electrodes

de-los-Santos-Álvarez

Analytical and Bioanalytical Chemistry

Miranda‐Ordieres

et al. 2004

115

A review of current strategies aimed at detecting nucleic acids (NA) using NA-modified solid electrodes reveals the versatility and potential of electrochemical detection in this field. What emerged at the beginning of 90s as a very promising detection system in DNA technology is now resulting in the first commercial devices. Many aspects of the experimental design, for example surface immobilisation and detection schemes, are outlined and evaluated. Although most approaches use hybridisation as the recognition reaction, those not based on hybridisation are also included. As is finally shown, great advances have been achieved, although further developments are required if electrochemical devices are to be suitable for routine measurement.