共查询到6条相似文献,搜索用时 0 毫秒
1.
Jing‐Jing Zhang Bin Wang Yan‐Fen Li Wen‐Li Jia Hui Cui Huai‐Sheng Wang 《Electroanalysis》2008,20(15):1684-1689
The study of DNA damage induced by Fenton reaction (Fe2+/H2O2) in vitro was performed based on the direct electrochemical oxidation of 8‐hydroxydeoxyguanosine (8‐OH‐dG), the biomarker of DNA oxidative damage, at an electrochemically modified glassy carbon electrode (GCE). The effects of antioxidants, such as ascorbic acid, and hydroxyl‐radical scavenger (mannitol) on the DNA damage were also investigated. 8‐OH‐dG, the oxidation product of guanine residues in DNA, has shown significantly oxidative peak on the electrochemically modified GCE. The oxidative peak current of 8‐OH‐dG was linear with the damaged DNA concentration in the range of 10–200 mg/L. The experimental results demonstrate that ascorbic acid has ambivalent effect on DNA oxidative stress. It can promote DNA oxidative damage when ascorbic acid concentration is below 1.5 mM and protect DNA from damage in the range of 1.5–2.5 mM. As a hydroxyl‐radical scavenger, mannitol inhibits significantly DNA oxidative damage. The influence of Fe2+, as reactant, and EDTA as iron chelator in the system were also studied. The proposed electrochemical method can be used for the estimation of DNA oxidative damage from new point of view. 相似文献
2.
Adel A. Abdelwahab Dong‐Min Kim Naveen M. Halappa Yoon‐Bo Shim 《Electroanalysis》2013,25(5):1178-1184
A simple detection method of ascorbic acid (AA) through selective catalytic oxidation has been developed using a novel conducting polymer poly‐3′‐(2‐aminopyrimidyl)‐2,2′:5′,2“‐terthiophene (pAPTT). The pAPTT electrode showed an excellent selectivity in facilitating the electron transfer of AA and blocked the interferences of cationic species due to the positively charged pAPTT film. This method proved to be effective in the determination of AA in the presence of various biological interfering species. The dynamic range of AA detection was from 10 to 200 µM and the detection limit was 1.4±0.06 µM. 相似文献
3.
《Electroanalysis》2005,17(17):1529-1533
The direct electrochemical oxidation of ascorbic acid at an edge plane pyrolytic graphite electrode (EPPG) is investigated and compared with other common carbon‐based electrodes, specifically glassy carbon, boron doped diamond and basal plane pyrolytic graphite. It is found that the EPPG electrode shows a significantly higher degree of electrochemical reversibility than the other electrode substrates giving rise to an analytically optimized limit of detection and sensitivity of 7.1×10?5 M and 0.065 A M?1 respectively. 相似文献
4.
《Electroanalysis》2006,18(11):1097-1104
Copolymerization of an osmium(II) functionalized pyrrole moiety, osmium‐bis‐N,N'‐(2,2′‐bipyridyl)‐N‐(pyridine‐4‐ylmethyl‐(8‐pyrrole‐1yl–octyl)‐amine)chloride ( I ) with 3‐methylthiophene was carried out. The resulting conducting polymer film exhibited a clear redox couple associated with the Os3+/2+ response and the familiar conducting polymer backbone signature. The effect of film thickness upon the redox properties of the copolymer was investigated in organic electrolyte solutions. Scanning electron micrographs (SEM) along with energy dispersive X‐ray (EDX) spectra of the copolymerized films were undertaken, both after formation and redox cycling in neutral buffer solution. These clearly show that electrolyte is incorporated into the polymer film upon redox cycling through the Os3+/2+ redox system. The Os3+/2+ response associated with the copolymer was seen to be significantly altered in the presence of ascorbic acid both in acidic and neutral pH buffer solutions. This pointed to an electrocatalytic reaction between the ascorbic acid and the Os3+ form of the copolymer. Under acidic conditions the copolymer film exhibited a sensitivity of 1.76 (±0.05) μA/mM with a limit of detection (LOD) of 1.45 μM for ascorbic acid. Under neutral pH conditions the copolymer exhibited a sensitivity of 19.26 (±1.05) μA/mM with a limit of detection (LOD) of 1.28 μM for ascorbic acid. 相似文献
5.
《Electroanalysis》2003,15(21):1655-1660
The electrochemical response of 5,5‐dithiobis(2‐nitrobenzoic acid) (DTNB) to increasing additions of thiol species has been examined at a boron doped diamond electrode. A reaction has been shown to occur with a range of biologically relevant thiols and proceeds via a CECC' process. A total thiol detection methodology has been developed showing that the sensitivities of the standard addition plots are independent of the individual thiol species added to the solution. The analytical utility of the reaction process has been assessed using chronoamperometry with the corresponding data producing detection limits of 5.7 μM, 4.4 μM and 5.8 μM for the detection of cysteine, homocysteine and glutathione respectively. 相似文献
6.
《Electroanalysis》2004,16(12):1051-1058
The voltammetric behavior of α‐ketoglutarate (α‐KG) at the hanging mercury drop electrode (HMDE) has been investigated in acetate buffer solution. Under the optimum experimental conditions (pH 4.5, 0.2 M NaAc‐HAc buffer solution), a sensitive reductive wave of α‐KG was obtained by linear scan voltammetry (LSV) and the peak potential was ?1.18 V (vs. SCE), which was an irreversible adsorption wave. The kinetic parameters of the electrode process were α=0.3 and ks=0.72 1/s. There was a linear relationship between peak current ip, α‐KG and α‐KG concentration in the range of 2×10?6–8×10?4 M α‐KG. The detection limit was 8×10?7 M and the relative standard deviation was 2.0% (Cα‐KG=8×10?4 M, n=10). Applications of the reductive wave of α‐KG for practical analysis were addressed as follows: (1) It can be used for the quantitative analysis of α‐KG in biological samples and the results agree well with those obtained from the established ultraviolet spectrophotometric method. (2) Utilizing the complexing effect between α‐KG and aluminum, a linear relationship holds between the decrease of peak current of α‐KG Δip and the added Al concentration Cequation/tex2gif-inf-5.gif in the range of 5.0×10?6–2.5×10?4 M. The detection limit was 2.2×10?6 M and the relative standard deviation was 3.1% (Cequation/tex2gif-inf-6.gif=4×10?5 M, n=10). It was successfully applied to the detection of aluminum in water and synthetic biological samples with satisfactory results, which were consistent with those of ICP‐AES. (3) It was also applied to study the effect of AlIII on the glutamate dehydrogenase (GDH) activity in the catalytically reaction of α‐KG+NH +NADH?L ‐glutamate+NAD++H2O by differential pulse polarography (DPP) technique. By monitoring DPP reductive currents of NAD+ and α‐KG, an elementary important result was found that Al could greatly affect the activity of GDH. This study could be attributed to intrinsic understanding of the aluminum's toxicity in enzyme reaction processes. 相似文献