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1.
《Electroanalysis》2006,18(9):911-917
Electrooxidation of methanol on glassy carbon (GC) electrode modified by optimum carbon supported Pt electrocatalyst (Pt‐C/GC) in acid media is investigated. The catalyst is prepared by ultrasonicating Pt/C powders in aqueous media. The activity of prepared Pt‐C/GC electrode is studied in potential range of 0–1000 mV (versus SCE) by cyclic voltammetry. The results showed that the Pt/C dispersed layer at the surface of glassy carbon electrode, behaves as an electrocatalyst for the oxidation of methanol in acid medium by optimum loading of Pt (0.2 mg cm?2). The electrochemical properties of prepared electrode are studied under various conditions. However the effect of various parameters in the catalytic enhancement of Pt/C, such as platinum loading, sulfuric acid concentration, different scan rates, different final potentials, and medium temperature are considered and examined. 相似文献
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微分脉冲伏安法检测扶他林片中的双氯芬酸钠 总被引:2,自引:0,他引:2
用微分脉冲伏安法在 +0 .6~ +1.2V(vs.SCE)范围内对双氯芬酸钠盐酸溶液进行循环扫描 ,发现在电位 0 .9V处有一灵敏的氧化峰 .该氧化峰的峰电流与双氯芬酸钠的浓度 (5 .0× 10 -7~ 6 .0× 10 -6mol/L)呈良好的线性关系 .在 2 .0× 10 -6mol/L双氯芬酸钠溶液中进行 10次实验 ,该峰的峰电流相对标准偏差为 3.5 % .用此法检测扶他林片中的双氯芬酸钠 ,所得结果与紫外分光光度法测定的结果一致 . 相似文献
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Polymer capable of specific binding to Cu-dipyridyl complex was prepared by molecular imprinting technology. The binding specificity of the polymer to the template (Cu-dipyridyl complex) was in vestigated by cyclic voltametric scanning using the carbon paste electrode modified by polymer particles in phosphate buffer solution. Factors that influence rebinding of the imprinted polymer were explored. The result demonstrated that the cycllic voltammetry was an efficient approach to explore interactions between template and imprinted polymers. 相似文献
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Direct Determination of Trace Dopamine in an Ascorbic Acid Solution at a Bare Glassy Carbon Electrode Using Differential Pulse Voltammetry 下载免费PDF全文
Lijian Sun Jing Chen Fangmin Zhao Na Liu Yingqiu Zhang Jianbo Jia Jianguo Wang 《Electroanalysis》2015,27(6):1411-1415
It is difficult to monitor dopamine (DA) accurately with a bare glassy carbon electrode because of the interference of ascorbic acid (AA). In this paper, a method for the determination of DA in an AA solution using differential pulse voltammetry was established. Because AA loses its electrochemical activity after being oxidized, hydrogen peroxide was used to oxidize AA, and the interference of AA was completely eliminated. As a result, trace DA could be directly determined in the AA solution with a bare glassy carbon electrode. When trace DA was determined in a 1.0 mmol L?1 AA solution, there was a wide linear range from 3.0×10?8 mol L?1 to 1.0×10?5 mol L?1. The application of this method was demonstrated by the selective measurement of DA in an injection without pretreatment. 相似文献
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采用数字模拟法对耦联酶催化反应体系的表面循环伏安行为进行了研究,讨论了介体氧化还原动力学、酶催化动力学及介体催化酶动力学等参数对循环伏安图的影响,并用实验进行了验证。 相似文献
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Glassy carbon electrodes were modified electrochemically by pretreatment in sulfate, phosphate or carbonate solutions by means of cycling the potential well into the positive limit of the solvent. Electrodes treated in this manner were then used to incorporate and concentrate a variety of redox species that were either cations or aromatic containing compounds, including Ru(bpy)2+3, Ru(NH3)3+6, Cu(NH3)2+4, ferrocene, methylviologen, 1,4-benzoquinone, anthraquinone-2-sulfonate, riboflavin, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). Surface-equivalent concentrations ranged from 5 × 10?9 to 1 × 10?7 mol cm?2 for electrodes pretreated for 10 min in sulfuric acid. An E1/2 vs. pH study of 1,4-benzoquinone, riboflavin, FMN and FAD in modified electrodes shows that the pKa values shift toward higher pH (nearly 2 pH units). Results concerning the incorporation of redox compounds detected only by mediation with other electroactive complexes and the study of the modified electrodes in electrocatalysis are also discussed. 相似文献
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用线扫溶出伏安法和循环伏安法研究了鸟嘌呤在玻碳电极上的电化学行为,鸟嘌呤的阳极锋电流与其浓度在1×10-7-5×10-4mol/L范围内有良好线性关系。讨论了实验条件,建立了测定鸟嘌呤的新分析方法,应用于生物样品中鸟嘌呤的测定,结果满意. 相似文献
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二氯喹啉酸在玻碳电极上的伏安行为及测定 总被引:2,自引:0,他引:2
应用循环伏安法(CV)和微分脉冲溶出伏安法(DPSV)在玻碳电极(GCE)上对二氯喹啉酸进行了研究,发现二氯喹啉酸在pH一=的B-R(Britton-Robinson)缓冲底液中于 0.954 V(vs.SCE)左右产生一个尖锐的阳极氧化峰.实验考察了pH值、富集时间、扫速、静止时间的影响.该法二氯喹啉酸在1.0×10-6~1.0×10-4 mol/L范围内与峰电流呈线性关系(r=0.998 8),检出限为6.0×10-7mol/L.用该方法对二氯喹啉酸进行了实际测定;对二氯喹啉酸的电极反应机理进行了初步探讨. 相似文献
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微分脉冲阴极溶出伏安法测定阿米卡星 总被引:1,自引:1,他引:0
硫酸阿米卡星(Am ikacin sulfate)是一种氨基糖苷酸类抗生素,化学名为O-3氨基-3-脱氧-а-D-蒲吡喃糖基-(1-6)-O-[6-氨基-6-脱氧-а-D-蒲吡喃糖基-(1-4)]-N-(4-氨基-2-羟基-1-氧丁基)-2-脱氧?D-链霉胺硫酸盐。目前报道的测定方法主要有高效液相法[1]、镍毛细管电泳法[2]。本文研究了阿米卡星在玻碳电极上的电化学行为。微分脉冲溶出伏安法是一种灵敏度很高的痕量分析方法,本文利用该方法对阿米卡星进行了测定,发现阿米卡星在pH=2的盐酸底液中,产生一灵敏的还原峰,可用于定量测定。平行测定了7次,RSD为2·05%,该方法可用于注射液及血清中… 相似文献
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Electrochemical oxidation of (?)‐epigallocatechin gallate (EGCG), the main monomer flavanol found in green tea, has been investigated over a wide pH range at a glassy‐carbon electrode using square‐wave voltammetry (SWV). Square‐wave voltammograms of (?)‐epigallocatechin (EGC) and gallic acid have been studied as well. The I–E profile of EGCG, i.e. the oxidation potentials and the current responses of the first and the second peak, is pH dependent. The oxidation of EGCG is a quasireversible process over the studied pH range, which was also confirmed by the non‐linear relationship between the peak currents and squre root of frequency. The best SWV responses for EGCG were obtained at pH 2.0, frequency of 100 Hz, step of 2 mV and amplitude of 50 mV. Under these conditions, linear responses for EGCG were obtained for concentrations from 1×10?7 M to 1×10?6 M, and calculated LOD and LOQ for the first oxidation peak were 6.59×10?8 M and 2.19×10?7 M, respectively. The proposed electroanalytical procedure was applied for the determination of EGCG content in green tea. Developed SWV methodology represents a potential analytical tool in determination of catechins in tea samples. 相似文献
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Jorge Ginja Teixeira Cristina Barrocas Dias Dora Martins Teixeira 《Electroanalysis》2009,21(21):2345-2353
The electrochemical behavior of pomiferin, a natural isoflavone with significant antioxidant, antidiabetic and antitumor properties, is reported here for the first time at a glassy carbon electrode (GCE). In order to understand the redox processes of this compound, its response was compared with the nonantioxidant isoflavone osajin. Based on cyclic and square‐wave voltammetric methods it was observed that pomiferin presents a quasireversible anodic peak, which was attributed to the oxidation of the catechol group, and that is strongly influenced by pH. This anodic process yields a well‐defined DPV response, which can be used for the analytical determination of this potential pharmotherapeutic isoflavone. 相似文献
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研究了以循环伏安法测定铁胺络合物还原强度的准确度及其影响因素,优化阴极电解液(包括硝酸铁、三乙醇胺、氢氧化钠、硝酸钙).实验表明,由循环伏安法测定的铁胺络合物还原强度与浸染染色法测得的比较,前者准确度好、稳定性高,而且操作方便快捷,在电化学还原染色生产和质量控制中具有重要的应用价值. 相似文献
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Daniela Pott Marinho Ballottin Leonardo Lataro Paim Nelson Ramos Stradiotto 《Electroanalysis》2013,25(7):1751-1755
A glassy carbon electrode chemically modified with nickel oxyhydroxide from a nickel hexacyanoferrate (NiHCF) film was used to determine glycerol in biodiesel by cyclic voltammetry. The modified electrode exhibited a linear response to glycerol concentration in the range from 0.05 to 0.35 mmol L?1, and a detection limit of 0.030 mmol L?1. The glycerol concentration found in the biodiesel sample was 0.156 mmol L?1. The method developed in this study showed a recovery of (100.3±5.0)%. 相似文献
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Maryam Khoshroo Abbas A. Rostami Saeed Yeganegi 《Monatshefte für Chemie / Chemical Monthly》2008,139(7):781-787
A glassy carbon (GC) surface modified with monolayer of 4-bromophenyl was examined as voltammetric electrode for some redox
systems. The modified electrode exhibited very slow electron transfer in comparison to the unmodified surface by factors which
varied with the redox systems. However, after scanning the modified electrode in 0.1 M tetrabutylammonium tetrafluoroborate (TBABF4) in acetonitrile from 0.4 to −1.1 V vs. Ag/AgCl for 20–25 cycles, the modified electrode showed much faster electron transfer kinetics, e.g., the results for Fe(CN)6
3−/4− were approaching those observed with unmodified surfaces. The effect is attributed to an apparently irreversible structural
change in the 4-bromophenyl monolayer, which increases the rate of electron tunneling. The transition to the conducting state
is associated with electron injection into the monolayer and causes a significant decrease in the calculated HOMO-LUMO gap
for the monolayer molecule. Once the monolayer is switched to the conducting state, it supports rapid electron exchange with
the redox system, but not with dopamine, which requires adsorption to the electrode surface. A conductive surface modified
electrode may have useful properties for electroanalytical applications and possibly in electrocatalysis.
Correspondence: Abbas A. Rostami, Department of Chemistry, Faculty Basic of Science, University of Mazandaran, Babolsar, Iran. 相似文献
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采用循环伏安法成功制备了氢氧化钴薄膜修饰玻碳电极。考察了影响膜电沉积的因素 ,确定成膜液最佳pH为7.5 ,最佳扫描电位范围为1.00~ -0.20V。讨论了成膜过程及机理 ,成膜关键是Co2 +在电极表面的氧化。制得的膜修饰电极具有表面吸附反应特征 ,表面覆盖量相当于5~6个单层的氧化还原活性物质。膜修饰电极具有良好的稳定性 ,并对H2O2 表现出较高的电催化活性。线性回归方程为 :ΔIpa(μA)=15.92+4.99×104c(H2O2)(mol·L -1)(r=0.9976 ,n=18) ,线性范围为1.72×10 -5~9.92×10 -3mol·L -1,检出限为4.25×10 -6mol·L -1(S/N=3)。 相似文献
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Shofu Matsuda Yuuki Okuda Yoshiki Obu Norio Nagayama Minoru Umeda 《Electroanalysis》2019,31(12):2466-2471
With the objective of understanding the kinetic redox properties of triphenylamine derivatives in association with chemical reactions, for their future application in functional organic semiconductor devices, the electrochemical characteristics of 4‐(2,2‐diphenylethenyl)‐N,N‐bis(4‐methylphenyl)‐benzenamine (TPA) were evaluated. Based on cyclic voltammograms of TPA on Pt disk electrodes with diameters of 300 μm and 10 μm at slow and fast scan rates in an acetonitrile solution, the TPA.+ is stable, while the TPA2+ is unstable. Importantly, the unstable TPA2+ appears to break down by a subsequent chemical reaction. A Cottrell plot analysis from chronoamperometry of a solution containing TPA reveals that both the first and second oxidations are one‐electron reactions. Concerning the stabilization mechanism of the first oxidation state of TPA, the results of molecular orbital calculations indicate that the electrons of the HOMO level are distributed in the triphenylamine group, which induces a resonance‐stabilized TPA.+. Based on these results, TPA/TPA.+ is suggested to have a sufficient stability for further application in organic semiconductor devices. 相似文献