采用粉末微电极技术改善电流型酶电极的输出性能

由于酶反应的特异性，酶电极在检测生物底物的工作中得到了较广泛的应用，然后电流型酶电极有以下的缺点，包括响应电流低，活性组份流失电极使用寿命下降以及响应电流的非线性等。本文根据粉末酶电极模型进行了动力学分析，得出在两极极端情况下粉末酶电极的电流响应动力学公式，以及由响应电流估算表观米氏常数的方法。采用了两种粉末酶电极（Ｃ－ＰＵ－ＧＯＤ和Ｃ－ＡＱ－ＤＢＦ－ＧＯＤ）对理论分析进行了验证。实验结果与理论推     

对插型阵列微带电极的制作及其电化学特性研究

用微电子光刻方法制作了对插型阵微带电极（ＩＤＡ），并通过ＳＥＭ对ＩＤＡ电极进行了表征，将微Ａｇ／ＡｇＣｌ参比电极和微铂丝对电极固定在ＩＤＡ电极附近，构成了微电解池，考察了该电极的循环伏安及计时电流特性，并用微带电极的扩散理论和Ｃｏｔｔｒｅｌｌ 公式对ＩＤＡ电极的准稳太电流进行了处理，指出了它们之间产生偏差的原因，研究了ＩＤＡ电极的“发生－收集”效应，测定了该电极的屏蔽因子、反馈因子和收集效率。     

线状铜电极在磷酸溶液中电流混沌振荡的同步行为

研究了恒电位下两个铜线电极在磷酸溶液中的电流混沌振荡行为,通过恒定不同的电位数值,改变单个电极的电流振荡混沌行为,研究了不同混沌间的相互作用.调整线电极间的距离,研究了电极间距对电流振荡行为的影响.实验中两电极的振荡间呈现了复杂的耦合作用,耦合后的频率与耦合前电极原有的频率不同.两电极的混沌电流振荡中呈现出同步、准周期同步和反相同步等现象.电极距离一定时,振荡波形差别很大的两电极的电流容易呈现反相同步和准周期同步,波形差别不大时容易产生同步.强的耦合导致电极间电流振荡的同步,电极距离的加大,电极间电流振荡难以产生同步.对耦合作用机制也进行了探讨.     

纳米MnO2超级电容器的研究

用固相合成法制备纳米MnO2，作为超级电容器材料，通过循环伏安、交流阻抗与恒电流充放电等测试手段对MnO2电极进行分析.结果表明,以1 mol•L－1 KOH为电解液， MnO2电极在－0.1～0.6 V(vs. Hg/HgO)的电压范围内具有良好的法拉第电容性能.在不同电流密度下，电极比容量达240.25到325.21 F•g－1.恒电流充放电5000次后，电极容量衰减不超过10％.     

微环电极上双电位阶跃计量电流和计量库仑法可逆波理论及…

推导了微环电极上双电位阶跃计时电流和计时库仑法可逆波理论方程式，并得到了解析表达式，对其电流电量曲线的特性进行了讨论。在亚铁氰化钾－氯化钾体系中，用金微环电极在自制的微机多功能电化学仪器上进行了实验验证，实验结果与理论相符。     

纳米电极上单个银纳米颗粒氧化电流分辨能力的研究

在单体电化学的研究中,提高信号分辨能力是一项挑战.缩小电极尺寸有利于对体系噪音电流的控制,有望提高电流的分辨能力.本研究制备了直径为480 nm的铂纳米圆盘电极,选用银纳米颗粒碰撞电极产生银电化学氧化行为作为模型,考察了纳米电极相对于微米电极在单体电化学信号分辨能力上的优化作用.研究表明,不同尺寸电极上观察到的银纳米颗粒的碰撞频率符合扩散控制的碰撞规律.说明单个电流信号对应于单个纳米颗粒的电化学氧化过程.同时,当电极尺寸缩小至纳米尺度后,噪音电流下降50%左右,提高了对银纳米颗粒碰撞电极过程中氧化电流的分辨能力.研究结果表明使用纳米电极能进一步提高对单体电化学中微小电流的检测能力.     

多晶光电化学电极的内部短路电流

本文提出多晶光电化学电极中存在暗区短路电流的概念及其测试方法,并用模拟电极体系及实际多晶电极加以验证。实验结果表明:暗区短路电流的大小随电极的制造工艺而不同。由此可见,存在暗区短路电流是多晶光电化学电极开路电压和输出电流较单晶为低的原因之一,因此,制备多晶电极时应注意使电极致密、孔隙度小。     

微环电极上双电位阶跃计时电流和计时库仑法可逆波理论及其验证

推导了微环电极上双电位阶跃计时电流和计时库仑法可逆波理论方程式，并得到了解析表达式。对其电流电量曲线的特性进行了讨论。在亚铁氰化钾－氯化钾体系中，用金微环电极在自制的微机多功能电化学仪器上进行了实验验证，实验结果与理论相符。     

电沉积氧化铈对烧结镍电极性能的影响

在烧结镍基体表面，预先电沉积一层氧化铈，通过电化浸渍得到镍电极，研究了预先电沉积氧化铈对烧结镍电极性能的影响。结果表明：与空白烧结镍电极相比，预先电沉积氧化铈（＋4），改善了烧结镍电极的大电流充放电性能和循环性能，增加了电极的可逆性，提高了电极的充电接受能力和活性物质利用率，减少了电极膨胀率，且当氧化铈的预先电沉积量为5％时，烧结镍电极的电极性能处于最佳。     

非接触法微电极阵列的制备及其电化学特性的研究

微电极阵列是指由多个电极集束在一起所组成韵外观单一的电极,其电流是各个单一电极电流的加和.这类电极保持了原来单一电极的特性,又可以获得较大的电流强度,提高了测量的灵敏度.     

Application of a gold electrode,modified by a self-assembled monolayer of 2-mercaptodecylhydroquinone,to the electroanalysis of hemoglobin

A gold electrode modified by a self-assembled monolayer of 2-mercaptodecylhydroquinone (H(2)Q(CH(2))(10)SH) was applied to investigate the electrochemical response of hemoglobin in aerated buffer solutions. Compared with a bare gold electrode, the monolayer of H(2)Q(CH(2))(10)SH could suppress the reduction wave of dissolved oxygen in the buffer while effectively promoting the rate of electron transfer between hemoglobin and the electrode. Thus, a convenient way for electroanalysis of hemoglobin in air was achieved at the H(2)Q(CH(2))(10)SH/Au electrode. A linear relationship existed between peak current and concentration of hemoglobin in the range 1 x 10(-7)-1 x 10(-6) mol L(-1).     

Electron transfer of heme proteins on the ITO electrode in polymer solvents

The redox reaction of poly(ethylene oxide) (PEO)-modified hemoglobin (PEO–Hb) was analyzed in PEO oligomers with cyclic voltammetry. The PEO–Hb was made soluble in PEO with molecular weight of 200 (PEO₂₀₀) containing 0.5 M KCI. Quasi-reversible redox signals of PEO–Hb were obtained by using an indium tin oxide (ITO) glass working electrode. PEO–Hb, cast on the ITO electrode, also showed the redox response in PEO with molecular weight of 400 (PEO₄₀₀). The peak current of PEO–Hb on the ITO electrode gradually increased during potential cycling. The effect of the scan rate on the quantity of electricity (Q) was analyzed after the peak current reached a constant value. The constant Q value was observed at the scan rate ranging from 30 to 500 mV/sec. The number of reactive PEO–Hb molecules was estimated from this constant Q-value. It was suggested that the electron transfer was carried out at the first layer of the PEO–Hb which was in direct contact with the ITO electrode. The quantity of electricity of PEO–Hb increased when the ITO electrode was first washed in an aqueous medium with ultrasonicator. This strongly suggested that the more effective surface area of the ITO electrode turned to be covered with PEO–Hb when the microporous region of the ITO particles was more hydrated.     

伏安法研究五元瓜环对Cu(Ⅱ)配合物的识别性能

利用伏安法研究了五元瓜环(记为Q[5])对Cu(Ⅱ)配合物的识别性能。结果表明:在pH 5.0的Na2(H2EDTA)介质中,扫描速度为100 mV.s-1时,Q[5]-[Cu(H2EDTA)H2O]配合物的电极反应为单电子准可逆氧化还原反应。摩尔比法测出Q[5]与[Cu(H2EDTA)H2O]作用比为2∶1,稳定常数为3.59×109 L2.mol-2。在所选择的实验条件下,Cu(Ⅱ)浓度在2×10-6~1.6×10-4 mol.L-1范围内,峰电流与其浓度具有较好的线性关系,方法回收率为99.4%~100.7%。     

Catalytic-voltammetric determination of the antioxidant tert-butylhydroxyanisole (BHA) at a nickel phthalocyanine modified carbon paste electrode

The voltammetric behaviour of the antioxidant tert-butylhydroxyanisole (BHA), at a carbon paste electrode modified with the electron mediator nickel phthalocyanine, is described, and a method for the determination of this antioxidant, based on its oxidation on the modified electrode, is proposed. Cyclic voltammograms showed a well-defined oxidation peak for BHA slightly shifted towards less positive potentials with respect to that obtained at the plain carbon paste electrode. The peak current measured at the modified electrode is considerably higher than that obtained at the unmodified electrode. A modifier percentage of 2%, a methanol percentage of 2% and a 0.1 mol/HClO(4) medium were chosen as working conditions. The i(p)vs v1 2 plot obtained by linear sweep voltammetry showed a linear relationship over the whole scan rate range studied (5-2000 mV/sec) which is typical of a diffusion-controlled current. Using differential pulse voltammetry at DeltaE = 50 mV, linear calibration graphs were obtained in the concentration ranges 1.0-30.0, 0.10-1.0 and 0.02-0.10 mg/l BHA. The detection limit was 0.0036 mg/l (2.0 x 10(-8) mol/l). Interferences from other substances commonly present in commercial antioxidant mixtures were tested. The developed method was applied to the determination of BHA in spiked potato flakes.     

环丙沙星－锰络合吸附波的研究

环丙沙星－锰络合吸附波的研究①张加玲樊惠芝潘景浩＊（山西大学化学系,太原０３０００６）环丙沙星（ｃｉｐｒｏｆｌｏｘａｃｉｎ简写ＣＰＦＸ）是新一代氟喹诺酮类抗菌药物之一,它的抗菌力强、抗菌谱宽,临床应用非常广泛．关于氟喹诺酮类抗菌药物与抗酸剂、维生素类...     

化学镀Ni—Co—P合金对Mm（NiCoAiMn）5贮氢合金电极动力学性能的影响

通过电化学方法,研究了化学镀Ni-Co-P合金对Mm(NiCoAlMn)5五元稀土贮氢合金电极动力学性能的影响,研究表明,引入很少量（1－2％）Co的Ni-Co-P合金镀层可有效地提高MH电极的交换电流密度io,极限电流密度iL及α相中氢的扩散系数Dα（H）,还研究了化学镀Ni-Co-P合金对稀土贮氢合金电极循环伏安（CV）曲线和阴,阳极极化曲线及对称因子β的影响,进而阐明了化学镀对MH电极过程动力学的影响。     

Self electro-catalysis of hydroquinone on gold electrode in aqueous un-buffered media

Redox behavior of hydroquinone (H₂Q) in an un-buffered aqueous medium at gold electrode is reported. In multiple scanned cyclic voltammograms, appearance of a new redox couple, splitting of H₂Q oxidation peak and anodic shift of original H₂Q redox peak were observed. Comparative studies of quinone (Q) under similar conditions establish the formation of surface confined Q as an intermediate. Electro-catalysis by the electro-generated Q monolayer is proposed to be responsible for the splitting of H₂Q oxidative wave in the cyclic voltammetry.     

电活化玻碳电极差分脉冲溶出伏安法测定磺胺嘧啶

采用线性循环溶出伏安法和差分脉冲溶出伏安法对磺胺嘧啶在电活化玻碳电极上的电化学行为进行了研究。玻碳电极在PBS溶液中(pH 7.0),用恒电位法在1.7 V阳极氧化400 s,在B-R缓冲溶液中,磺胺嘧啶在1.02V(vs.Ag/AgCl)处有一良好的氧化峰,在0.02～0.25 V/s范围内,其氧化峰电流与扫描速率呈良好线性关系,表明电极过程为受吸附控制的不可逆过程。差分脉冲溶出伏安法的氧化峰电流(Ipa)与磺胺嘧啶浓度1×10-6～1×10-4mol/L范围内呈良好的线性关系(r=0.9977),检出限为8.7×10-7mol/L(S/N=3)。方法已用于分析磺胺嘧啶片剂的分析。     

Voltammetric Determination of Uric Acid with a Glassy Carbon Electrode Coated by Paste of Multiwalled Carbon Nanotubes and Ionic Liquid

The voltammetric behavior of uric acid (UA) has been studied at a multiwalled carbon nanotube‐ionic liquid (i.e., 1‐butyl‐3‐methylimidazolium hexafluorophosphate, BMIMPF₆) paste coated glassy carbon electrode (MWNTs‐BMIMPF₆/GC). It is found that UA can effectively accumulate at this electrode and cause a sensitive anodic peak at about 0.49 V (vs. SCE) in pH 4.0 phosphate buffer solutions. Experimental parameters influencing the response of the electrode, such as solution pH and accumulation time, are optimized for uric acid determination. Under the optimum conditions, the anodic peak current is linear to UA concentration in the range of 1.0×10^?8 M to 1.0×10^?6 M and 2.0×10^?6 M to 2.0×10^?5 M. The detection limit is 5.0×10^?9 M for 180 s accumulation on open circuit. The electrode can be regenerated by successively cycling in a blank solution for about 3 min and exhibits good reproducibility. A 1.0×10^?6 M UA solution is measured for eight times using the same electrode regenerated after every determination, and the relative standard deviation (RSD) of the peak current is 3.2%. As for different electrodes fabricated by the same way the RSD (i.e., the electrode to electrode deviation) is 4.2%(n=9). This method has been applied to the determination of UA in human urine samples, and the recoveries are 99%–100.6%. In addition, comparison is made between MWNTs‐BMIMPF₆/GC and MWNTs/GC. Results show that the MWNTs‐BMIMPF₆/GC exhibits higher sensitivity, selectivity and ratio of peak current to background current.     

Electrochemical oxidation and determination of methylparaben at overoxidized polypyrrole film modified a boron-doped diamond electrode

Electrochemical oxidation of methylparaben (MP) is studied on an overoxidized polypyrrole (OPPy)-modified boron-doped diamond electrode using the cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. The OPPy-modified BDD electrode displays the catalytic activity of electrooxidation of methylparaben. The modification of BDD electrode surface results in higher values of recorded oxidation currents of the methylparaben than on a bare BDD electrode. The diffusion character of recorded current is determined on the basis of the relation between the current and the scan rate. The linear relationship between methylparaben oxidation peak current is obtained in the range 1.57?×?10^??6–2.06?×?10^??5 mol L^??1. A new voltammetric procedure is proposed to quantify methylparaben in cosmetic products using an overoxidized polypyrrole (OPPy)-modified BDD electrode. The results are compared to the HPLC technique described in the literature as the reference method.