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Phytic acid (PA) with its unique structure was attached to a glassy carbon electrode (GCE) to form PA/GCE modified electrode which was characterized by electrochemical impedance. The electrochemical behavior of cytochrome c (Cyt c) on the PA/GCE modified electrode was explored by cyclic voltammetry and differential pulse voltammetry. The Cyt c displayed a quasi-reversible redox process on PA modified electrode pH 7.0 phosphate buffer solution with a formal potential (E 0′) of 57 mV (versus Ag/AgCl). The peak currents were linearly related to the square root of the scan rate in the range of 20–120 mV·s?1. The electron transfer rate constant was determined to be 12.5 s?1. The PA/GCE modified electrode was applied to the determination of Cyt c, in the range of 5?×?10?6 to 3?×?10?4 M, the currents increase linearly to the Cyt c concentration with a correlation coefficient 0.9981. The detection limit was 1?×?10?6 M (signal/noise?=?3). 相似文献
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The electrochemical behavior of isorhamnetin (ISO) at a glassy carbon electrode was studied in a phosphate buffer solution (PBS) of pH 4.0 by cyclic voltammetry (CV) and differential pulse voltammetric method (DPV). A well-defined redox wave of ISO involving one electrons and one proton appeared. The electrode reaction is a reactant weak adsorption-controlled process with a charge transfer coefficient (α) of 0.586. Based on the understanding of the electrochemical process of ISO at the glassy carbon electrode, analysis of ISO can be realized. Under optimal conditions, the oxidation peak current showed linear dependence on the concentration of ISO in the range of 1.0 × 10−8 to 4.0 × 10−7 M and 1.0 × 10−6 to 1.0 × 10−5 M. The detection limit is 5.0 × 10−9 M. This method has been successfully applied to the detection of ISO in tablets. 相似文献
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Aghamiri Zahra Sadat Mohsennia Mohsen Rafiee-Pour Hossain-Ali 《Journal of Solid State Electrochemistry》2019,23(7):2233-2242
Journal of Solid State Electrochemistry - A modified electrode PAN/PPY/cMWCNTs composed of polyaniline/polypyrrole (PAN/PPY) bilayer conducting polymer film, carboxylated multi-walled carbon... 相似文献
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胡椒碱在碳纳米管修饰电极上的电化学行为研究 总被引:1,自引:1,他引:0
研究了胡椒碱在碳纳米管修饰电极上的电化学行为,在pH为6.4的磷酸盐缓冲溶液中,胡椒碱在-1.12V(vs.SCE)处有一灵敏的还原峰.与裸电极相比,还原峰电位明显正移,峰电流显著增加,表明该修饰电极对胡椒碱的还原反应具有明显的催化作用.峰电流与胡椒碱的浓度在10-6~10-5mol/L范围内呈良好的线性关系(r=0.995),检出限为2.0×10-7mol/L.同时,计算了电荷转移数和扩散系数,考查了修饰电极的重现性,7次平行测量的RSD为4.96%. 相似文献
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The adsorptive and electrochemical behaviors of clozapine (CLZ) were investigated on a glassy carbon electrode that was electrochemically treated by anodic oxidation at +1.8 V, following potential cycling in the potential range from -0.8 to 1.0 V vs. Ag/AgCl reference electrode. Based on the obtained electrochemical results, an electrochemical-chemical (EC) mechanism was proposed to explain the electrochemical oxidation of CLZ. The resulting electrochemically pretreated glassy carbon electrode (EPGCE) showed good activity to improve the electrochemical response of the drug. CLZ was accumulated in a phosphate buffer (pH 6) at a certain time, and then determined by differential pulse voltammetry. The anodic and cathodic peak currents showed a linear function in the concentration ranges of 0.1 - 1, 1 - 10 and 10 - 100 microM with various accumulation times. The proposed method was successfully used for the determination of CLZ in pharmaceutical preparations. The preconcentration medium-exchange approach was utilized for the selective determination of the drug in spiked urine samples with satisfactory results. The recovery levels of the method reached 96% (RSD, 1.8%) and 90% (RSD, 2.8%) for urine and plasma samples, respectively. 相似文献
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对氯酚在碳纳米管修饰玻碳电极上的电化学行为研究 总被引:1,自引:0,他引:1
研究了对氯酚在多壁碳纳米管修饰玻碳电极(MWNTs/GC)上的电化学行为。MWNTs/GC电极对对氯酚具有良好的电催化作用,相比玻碳电极对氯酚的氧化峰电位负移76 mV,峰电流达到玻碳电极上的8倍。通过线性扫描伏安法研究了富集时间、溶液pH和扫描速率对对氯酚氧化的影响。并采用计时电流法研究了氧化峰电流与对氯酚的浓度关系,结果显示峰电流与对氯酚的浓度在2.0×10^-7-2.0×10^-4mol/L范围内呈良好线性关系,检出限为8.8×10-8mol/L(S/N=3)。放置7 d后,对氯酚在碳纳米管上的峰电流仍能达到最初电流的96.2%,表明电极的稳定性较好。 相似文献
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Cytochrome c (Cyt c) was successfully immobilized on L-cysteine modified gold electrode by multicyclic voltammetry method. The electrochemical behavior of Cyt c on the L-cysteine modified electrode was explored. In 0.10 M, pH 7.0 phosphate buffer solution (PBS), Cyt c showed a quasi-reversible electrochemical redox behavior with E(pc)=0.180 V, E(pa)=0.208 V (versus Ag/AgCl). The Cyt c/L-cysteine modified electrode gave an excellent electrocatalytic activity towards the oxidation of nitric oxide, and the catalysis currents were proportional to the nitric oxide concentration in the range of 7.0 x 10(-7) to 1.0 x 10(-5) M, the linear regression equation is I (microA)=-0.124-0.003 C(NO) (microM), with a correlation coefficient 0.996, The detection limit was 3.0 x 10(-7) M (times the ratio of signal to noise, S/N=3). 相似文献
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Hamid R. Zare Zahra Sobhani M. Mazloum-Ardakani 《Journal of Solid State Electrochemistry》2007,11(7):971-979
By immobilizing rutin at the surface of a glassy carbon electrode (GCE) modified with multi-wall carbon nanotubes (MWCNT),
a new modified electrode has been fabricated and its electrochemical behavior was investigated by cyclic voltammetry. Cyclic
voltammograms of the resulting modified electrode show stable and a well defined redox couple with surface confined characteristics.
The results show that the reversibility of rutin is significantly improved at a MWCNT modified GCE in comparison with GCE
alone. The charge transfer coefficient, α, was calculated to be 0.4, and charge transfer rate constant, ks, was 46.7 s−1 in pH 8, indicating great facilitation of the electron transfer between rutin and MWCNT deposited on the electrode surface.
The rutin MWCNT (RMWCNT) modified GCE showed excellent mediation of hydrazine oxidation: a decrease in the overvoltage of
hydrazine electrooxidation was observed as well as a dramatic increase in the peak current compared to that seen at a rutin
modified GCE (RMGCE), activated GCE or bare GCE. Hydrazine was determined amperometrically at the surface of RMWCNT modified
GCE in pH 8. Under the optimized conditions the calibration curve is linear in the concentration range 2.0–190.0 μM hydrazine.
The detection limit and sensitivity are 0.61 μM and 0.0656 μA μM−1, respectively. Finally the kinetic parameters of the electron transfer coefficient, α, the heterogeneous rate constant of
dependent to different potentials, k′(E), and the standard heterogeneous rate constant, k0, for oxidation of hydrazine at the RMWCNT surface were determined using various electrochemical methods. The advantages of
this modified electrode for hydrazine determination are high sensitivity, excellent catalytic activity, short response time,
wide linear range, and high exchange current density. 相似文献
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In this paper, a novel biosensor was prepared by immobilizing glucose oxidase (GOx) on carbon nanotube-gold-titania nanocomposites (CNT/Au/TiO2) modified glassy carbon electrode (GCE). SEM was initially used to investigate the surface morphology of CNT/Au/TiO2 nanocomposites modified GCE, indicating the formation of the nano-porous structure which could readily facilitate the attachment of GOx on the electrode surface. Cyclic voltammogram (CV) and electrochemical impedance spectrum (EIS) were further utilized to explore relevant electrochemical activity on CNT]Au/TiO2 nanocomposites modified GCE. The observations demonstrated that the immobilized GOx could efficiently execute its bioelectrocatalytic activity for the oxidation of glucose. The biosensor exhibited a wider linearity range from 0.1 mmol L-1 to 8 mmol L^-1 glucose with a detection limit of 0.077 mmol L^- 1. 相似文献
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Sridharan D Manoharan SP Palaniswamy N 《Bioelectrochemistry (Amsterdam, Netherlands)》2011,82(2):135-139
Marine and freshwater biofilm usually shift the open circuit potential (OCP) of stainless steel towards the electropositive direction by + 450 mV vs SCE. The nature of oxide film and bacterial metabolism were also correlated with ennoblement process by various investigators. Glassy carbon electrode (GCE) was used in the present study and a shifting of potential in the positive side (+ 450 mV) was noticed. It indicates that biofilm contributes to the ennoblement process without any n/p-type semiconducting oxide film. The nature of the cathodic curve for the biofilm covered GCE is compared with the previous literature on the electrochemical behavior of stainless steel. The present study explains the oxidation and reduction peaks of biofilm covered GCE by cyclic voltammetry. Electrochemical impedance result reveals the diffusion process within the manganese biofilm. The present study confirms the previous investigations that the manganese biofilm rules the electrochemical behavior of materials and suggests that oxide film is not necessary to assist the ennoblement process. 相似文献
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通过循环伏安法(CV)研究了玻碳电极上邻仲丁基苯酚(OSBP)的电化学行为.结果显示:在pH=8.0的磷酸盐缓冲液中,OSBP在玻碳电极上发生的氧化反应是受扩散控制的不可逆等电子、质子转移过程,且氧化产物部分被还原.氧化峰电流与浓度在5.0×10~(-6)~2.0×10~(-4)mol·L~(-1)之间呈良好的线性关系,检出限(S/N=3)为6.60×10~7mol·L~(-1).重复测定的相对标准偏差(RSD)为4.48%(n=7),加标回收率为86.2%~100.5%.结果令人满意. 相似文献
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Yuanzhi Song Yang Song Wen Xie Deqing Shi 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(9):1467-1474
DFT (B3LY/6-31G (d, p) and B3LYP/cc-PVDZ) calculations are performed for deoxidized dopamine (DA(R)) and its oxidized form (DA(O)). The electrochemistry of dopamine (DA) was studied by cyclic voltammetry (CV) at a glassy carbon electrode modified by Nafion
multiwalled carbon nanotubes (MWNTs) in phosphate buffers at pH 5.4, showing that the standard electrode potential of a half
reaction for DA(O), H+/DA(R) is 0.74 V. This experimental standard electrode potential of the half reaction is consistent with those of 0.65 and 0.69
V calculated using the energies of solvation and the sum of the electronic and thermal free energies of DA(R) and DA(O). The frontier orbital theory and Mulliken charges of molecules explain the electrochemical behavior of CV at a modified electrode
well. The effects of oxygen on DA(R) in blood and drug are also discussed according to equilibrium theory. The modified electrode was successful for determination
of the content of pharmaceutical DA.
The text was submitted by the authors in English. 相似文献
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采用线性扫描伏安法和循环伏安法研究了盐酸阿霉素在玻碳电极上的电化学行为及电极反应机理,优化了测定盐酸阿霉素的各实验参数。结果表明,在0.01 mol/L的HCl溶液中,盐酸阿霉素在-0.40 V处出现(vs.SCE)一灵敏的还原峰,峰电流与其溶液浓度在5.0×10-8~1.0×10-6mol/L(r=0.999)和1.0×10-6~1.0×10-5mol/L(r=0.998)范围内呈良好的线性关系,检出限为1.0×10-8mol/L。并用循环伏安法研究了盐酸阿霉素的峰电流性质,发现电极反应属于准可逆过程,出现一对灵敏的氧化还原峰,体系属准可逆吸附波。利用盐酸阿霉素在玻碳电极的电化学行为建立的分析方法可用于盐酸阿霉素的质量监控及药代动力学研究。 相似文献