氯过氧化物酶-聚L-赖氨酸/GC电极的电化学特性

应用电化学方法在玻碳电极上修饰聚L-赖氨酸膜,以1-乙基-(3-二甲基氨基丙基)碳二亚胺盐酸盐做交联剂,固定氯过氧化物酶.修饰电极的循环伏安曲线呈现一对可逆的氧化还原峰,表明聚L-赖氨酸能够很好地促进氯过氧化物酶在电极表面的直接电子传递,这是一个受吸附控制并伴随有质子转移的准可逆电子传递过程.该电极有很好的稳定性,并能显著地电催化氧的电化学还原反应.     

氯过氧化物酶修饰电极对一氯二甲酮的催化氯化

通过将氯过氧化物酶溶液(Chloroperoxidase, CPO)与Nafion分散的单壁碳纳米管分散液混合后直接滴涂到玻碳电极表面制得修饰电极. 这个固定了氯过氧化物酶的碳纳米管修饰玻碳电极, 在pH=5.0的磷酸缓冲溶液中测得的循环伏安曲线上有一对准可逆的氧化还原电流峰, 经过与裸电极和没有固定氯过氧化物酶的碳纳米管修饰电极上测得的循环伏安行为对比后确认, 碳纳米管对氯过氧化物酶与电极之间的电子传递反应具有很好的促进作用. 利用该修饰电极能催化一氯二甲酮氯化为二氯二甲酮, 无需添加过氧化氢作为反应启动剂, 紫外光谱的测试结果表明, 每摩尔氯过氧化物酶可催化氯化4.0×105 mol 的一氯二甲酮, 表现出很高的催化效率.     

氯过氧化物酶在碳纳米管修饰电极上的直接电化学研究

将氯过氧化物酶固定到单壁碳纳米管修饰玻碳电极,其循环伏安曲线出现一对准可逆氧化还原峰,说明碳纳米管能够很好地促进氯过氧化物酶在电极表面的直接电子传递.该过程与溶液pH值有关,可指认氯过氧化物酶在电极表面发生的是一电子一质子传递反应.该修饰电极制作简单,性能稳定,且对氧还原具有很好的电催化效应.     

Ionic liquid modified GC electrode for the direct electrochemistry of chloroperoxidase

Chloropcroxidase （CPO） was immobilized by konjac glucomannan （KGM） on the 1-butyl-3-methyl imidazolium tetrafluoroborate [BMIM][BF4]/Nafion modified glassy carbon eloctrode. The electrochemical behaviors of the immobilized CPO were investigated by cyclic voltammetry. The results showed that CPO was successfully immobilized on the GCE and underwent fast direct electron transfer reactions with the formal potential at -0.3 V vs. SCE. The modified electrode showed a good catalytic activity for elcctrocatalytical reduction of O2 and H2O2.     

三维有序金掺杂纳米TiO_2修饰电极用于抗肿瘤药物与DNA相互作用的研究

利用模板法在氧化铟锡(ITO)电极表面制备了三维有序多孔结构的金掺杂纳米Ti O2薄膜修饰电极(3DOM GTD/ITO),并在此修饰电极上成功固定小牛胸腺DNA(ct DNA),从而构建了一种新型的DNA生物传感器(DNA/3DOM GTD/ITO),并通过透射电镜(TEM)、扫描电镜(SEM)对修饰电极的表面形貌进行表征。采用电化学交流阻抗(EIS)法研究了ct DNA在3DOM GTD/ITO修饰电极表面的固定情况,结果表明,ct DNA已被成功地固定在3DOM GTD/ITO修饰电极表面。采用循环伏安法、微分脉冲伏安法等电化学方法研究了抗肿瘤药物槲皮素(Qu)在3DOM GTD/ITO修饰电极表面的电化学性质及与ct DNA的相互作用。结果表明,Qu在3DOM GTD/ITO修饰电极表面有1对准可逆的氧化还原峰,其氧化还原反应为2电子和2质子的转移过程。Qu可与固定在修饰电极上的ct DNA发生较强的结合作用,其结合常数(K)为3.61×106L/mol。循环伏安实验、紫外-可见吸收光谱、分子荧光光谱、圆二色性光谱均表明Qu与ct DNA之间的相互作用模式为嵌插作用。Qu与ct DNA的碱基结合具有序列选择性,对Qu与聚(d G-d C)及聚(d A-d T)的结合常数进行计算,得到结合常数比K(d G-d C)/K(d A-d T)=3.5,表明Qu与ct DNA发生嵌插作用时更倾向于结合在GC富集区域。     

氯过氧化物酶修饰电极用于岩白菜素的电催化氯化

将氯过氧化物酶(CPO)与双十二烷基二甲基溴化铵(DDAB)混合后滴涂于玻碳(GC)电极表面, 制得CPO-DDAB/GC修饰电极. 循环伏安结果显示, 固定在电极表面的CPO可与电极之间发生直接的电子传递作用. 利用高效液相色谱-质谱联用技术对反应产物进行表征, 结果显示, 以该CPO修饰电极为工作电极, 在氧气饱和的氯化钾-岩白菜素溶液中, 利用CPO催化氧还原生成的过氧化氢可进一步驱动CPO对岩白菜素的催化氯化反应. 经估算总转化数(TTN)达到13600, 即1 mol CPO可催化13600 mol岩白菜素.     

聚邻苯二胺/镍氢氧化物修饰电极的研究

采用循环伏安法(CV)在聚邻苯二胺修饰玻碳电极表面络合Ni2+,然后将其置于NaOH溶液中CV扫描成功制备了镍氢氧化物/聚邻苯二胺/玻碳修饰电极(Ni(OH)2/PoPD/GC).通过CV探讨了聚合和负载机理,电化学交流阻抗谱(EIS)表征了电极修饰过程中界面阻抗变化,扫描电镜表征了PoPD膜负载Ni(OH)2后的形态...     

铁铂核壳纳米粒子修饰玻碳电极制备及对亚硝酸盐还原的电催化性能

通过循环伏安法（CV）在玻碳（GC）电极表面电沉积出分布较为均匀的纳米Fe粒子,制得纳米Fe粒子修饰的GC（纳米Fe/GC）电极,再经“电荷置换”制得具有Fe核Pt壳结构的纳米粒子修饰的（纳米PtFe/GC）电极。 SEM结果显示,纳米Fe/GC和纳米PtFe/GC表面粒子的形貌均呈立方体形,分布较为均匀,粒径在60 nm左右。 纳米PtFe/GC电极对亚硝酸盐的还原具有很高的电催化活性。 3种电极的电催化活性顺序依次为：纳米Fe/GC＜纳米Pt/GC＜纳米PtFe/GC。 相对于纳米Pt/GC电极,纳米PtFe/GC电极的起始还原电位（Ei）正移了0.14 V,还原峰电流（ip）增大了3倍。     

新型Fe3O4纳米颗粒修饰玻碳电极对头孢噻肟钠的电催化还原及其测定

采用滴涂法将Fe3O4磁性纳米颗粒修饰在玻碳电极上,制得新型纳米Fe3O4修饰电极(Fe3O4-np/GC 电极).X射线衍射光谱表明,纳米Fe3O4为面心立方尖晶石结构,透射电子显微镜表明,纳米Fe3O4粒径15～20 nm的微球结构.采用扫描电子显微镜和交流阻抗法(EIS)对修饰电极表面进行了表征,发现纳米Fe3O4在电极表面形成了均匀的修饰膜.采用循环伏安法(CV)、微分脉冲伏安法(DPV)研究了头孢噻肟钠(CS)在修饰电极上的电化学行为及动力学性质,结果表明,CS在Fe3O4-np/GC电极上有敏锐的催化还原峰,且CS的还原峰电流与其浓度在7.0×10-8～1 ×10-6和1 ×10-6～4.5×10-5 mol/L范围内呈线性关系;检出限达到5.0×10-8 mol/L.该方法可用于市售头孢噻肟钠针剂中CS含量的测定,加标回收率达到96.6％～102.7％.     

Voltammetry of the Erythromycin-Modified Glassy Carbon Electrode and Interaction With Dna

ABSTRACT

The chemically modified electrode (CME) which was constructed by covalently attaching Erythromycin (ERM) to a glassy carbon (GC) surface was investigated in Tris-HCl buffer (pH=6.0) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). In the potential range -0.5 to +0.4V, CME yields a pair of stable redox waves. It is the carbonyl group of the ERM molecule immobilized on the GC surface that behaves as a two-electron redox process involving one proton. The interaction of CME with DNA was also studied by DPV. The CME shows the same interaction with DNA as that in the solution. And the interactive model between ERM and DNA was proved by fluorescence in aqueous solutions.     

CoSALEN/APO-5复合材料的制备及其电催化还原氧的性能

将金属钴离子引入磷酸铝分子筛APO-5制得CoAPO-5分子筛,再把N,N-双水杨醛缩乙二胺(SALEN)希夫碱通过扩散进入CoAPO-5分子筛孔道并与其中的钴离子配位,形成了CoSALEN配合物,构成CoSALEN/APO-5复合材料.应用物理吸附法,以聚苯乙烯(PS)作粘结剂,将CoSALEN/APO-5涂敷在玻碳电极表面制成修饰电极PS/CoSALEN/APO-5/GCE.循环伏安法(CV)、计时电流法(CA)研究了该修饰电极在不同pH电解质溶液中的电化学行为以及对分子氧的催化还原作用.结果表明,制备的修饰电极能有效地催化分子氧的四电子还原,即氧气被电催化还原为水,据此提出可能的氧还原机理.     

聚中性红修饰玻碳电极葡萄糖生物传感器

以中性红为电子媒介体,电聚合于Nafion修饰的玻碳电极表面,以戊二醛作交联剂固定葡萄糖氧化酶,最后覆盖一层Nafion膜防止酶流失,构建一种新型葡萄糖生物传感器.详细探讨了传感器的电化学性能及对葡萄糖的最佳响应条件.结果表明,30℃时,传感器在pH 7.0的PBS中对葡萄糖的线性响应范围为1.0×10-5~5.0×10-3mol.L-1.该传感器制作简单、性能优良,有潜在应用前景.     

Cyclic voltammetric investigation of Eu<Superscript>3+</Superscript> on a MWCNTs/SDS-modified glassy carbon (GC) electrode

Electrochemical reduction behavior of Eu³⁺ on a multi-walled carbon nanotubes (MWCNTs)/sodium lauryl sulfate (SDS) (MWCNTs/SDS)-modified glassy carbon (GC) electrode was investigated by cyclic voltammetry (CV). Results indicated that the electrochemical reduction process of Eu³⁺ at the MWCNTs/SDS-modified GC electrode is a quasi-reversible and diffusion-controlled process. The value of standard rate constant (k _s) at the MWCNTs/SDS-modified GC electrode was estimated to 1.96 × 10⁻² cm s⁻¹. CV studies showed that the electrochemical response of Eu³⁺ was directly related to the ratio of MWCNTs to SDS, and the tube diameter of MWCNTs had a slight influence on the electrochemical behavior of Eu³⁺, whereas the tube length. of MWCNTs had a strong influence. CVs results also proved that s-MWCNTs (with shorter tube length)-modified GC electrode showed better response to the electrochemical reaction of Eu³⁺.     

金复合介孔SBA-15吸附血红蛋白在H2O2电催化反应中的应用

以P123嵌段共聚物表面活性剂为模板剂制备介孔氧化硅SBA-15,并用沉积-沉淀(DP)法在SBA-15介孔表面负载纳米Au颗粒制备得到金复合介孔SBA-15材料(Au-SBA-15).再以Au-SBA-15材料制备玻碳修饰电极,将血红蛋白固定于修饰电极上用循环伏安法考察其对不同浓度H₂O₂溶液的电催化反应.在固定了血红蛋白的Hb/Au-SBA-15/GC修饰电极上,H₂O₂在+0.95 V处出现了氧化峰,且随着H₂O₂浓度的增大峰电流不断增加,说明金复合介孔氧化硅材料具有良好的生物兼容性,有利于血红蛋白的固定,其修饰电极对H₂O₂溶液具有一定的电催化作用.     

Disposable electrochemical biosensor with multiwalled carbon nanotubes-chitosan composite layer for the detection of deep DNA damage.

A novel electrochemical DNA-based biosensor for the detection of deep DNA damage was designed employing the bionanocomposite layer of multiwalled carbon nanotubes (MWNT) in chitosan (CHIT) deposited on a screen printed carbon electrode (SPCE). The biocomponent represented by double-stranded (ds) herring sperm DNA was immobilized on this composite using layer-by-layer coverage to form a robust film. Individual and complex electrode modifiers are characterized by a differential pulse voltammetry (DPV) with the DNA redox marker [Co(phen)(3)](3+), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) with [Fe(CN)(6)](3-) as a redox probe in a phosphate buffer solution (PBS). A good correlation between the CV and EIS parameters has been found, thus confirming a strong effect of MWNT on the enhancement of the electroconductivity of the electrode surface and that of CHIT on the MWNT distribution at the electrode surface. Differences between the CV and EIS signals of the electrodes without and with DNA are used to detect deep damage to DNA, advantageously using simple working procedures in the same experiment.     

Fabrication of Chitosan‐Multiwall Carbon Nanotube Nanocomposite Containing Ferri/Ferrocyanide: Application for Simultaneous Detection of D‐Penicillamine and Tryptophan

We report a simple and effective strategy for fabrication of the nanocomposite containing chitosan (CS) and multiwall carbon nanotube (MWNT) coated on a glassy carbon electrode (GCE). The characterization of the modified electrode (CS‐MWNT/GC) was carried out using scanning electron microscopy (SEM) and UV–vis absorption spectroscopy. The electrochemical behavior of CS‐MWNT/GC electrode was investigated and compared with the electrochemical behavior of chitosan modified GC (CS/GC), multiwalled carbon nanotube modified GC (MWNT/GC) and unmodified GC using cyclic voltammetry (CV) and electron impedance spectroscopy (EIS). The chitosan films are electrochemically inactive; similar background charging currents are observed at bare GC. The chitosan films are permeable to anionic Fe(CN)₆^3?/4? (FC) redox couple. Electrochemical parameters, including apparent diffusion coefficient for the Fe(CN)₆^3?/4? redox probe at FC/CS‐MWNT/GC electrode is comparable to values reported for cast chitosan films. This modified electrode also showed electrocatalytic effect for the simultaneous determination of D‐penicillamine (D‐PA) and tryptophan (Trp). The detection limit of 0.9 μM and 4.0 μM for D‐PA and Trp, respectively, makes this nanocomposite very suitable for determination of them with good sensitivity.     

黄芩素在聚-L-赖氨酸修饰电极上的电化学研究

<研究了黄芩素(baicalein, 缩写BAI)在玻碳电极(GCE)与聚-L-赖氨酸修饰的玻碳电极(PLL/GCE)上的电化学行为. 发现BAI不能在裸玻碳电极上产生明显的氧化还原信号, 但在PLL/GCE上有一对可逆性较好的氧化还原峰出现. 在最佳实验条件下, 氧化峰电流与BAI的浓度在5.0×10－7～1.0×10－5 mol/L范围内呈良好的线性关系, 相关系数R为0.998, BAI检测限为4.8×10－8 mol/L(信号与噪声比S/N＝3). 配10份相同浓度溶液, 每次测定后需重新修饰电极, 连续测定10次, 所得结果的相对标准偏差(RSD)为4.3%, 平均峰电流为1.48 μA. 这表明修饰电极具有良好的重现性. 将该方法用于BAI在尿样中的回收率分析, 结果令人满意.     

三维有序石墨烯掺杂纳米二氧化钛酶生物传感器

采用模板法在氧化铟锡电极上制备了三维有序多孔结构的石墨烯掺杂纳米二氧化钛修饰电极,并在此修饰电极上成功固定了过氧化氢酶,从而构建了一种新型的H2O2生物传感器。 通过循环伏安、交流阻抗及计时电流等方法研究了该修饰电极的电化学特性,实验结果表明,该修饰电极对H2O2有良好的电催化作用,对H2O2的检测线性范围为3.0×10-6~3.6×10-3 mol/L,检测限为4.2×10-7 mol/L(S/N=3);且传感器响应迅速、灵敏度高、重现性和稳定性好。     

A Novel Polycatechol/Ordered Mesoporous Carbon Composite Film Modified Electrode and Its Electrocatalytic Application

Polycatechol (PCC) was prepared by electropolymerizing catechol (CC) on the surface of an ordered mesoporous carbon (OMC) modified electrode for the first time. Scanning electron microscopy (SEM) and cyclic voltammetry (CV) were used to characterize the structure and electrochemical behaviors of PCC/OMC nanocomposite film. Compared with the bare GC and OMC/GC electrodes, the PCC/OMC/GC electrode exhibits a good electrocatalysis toward the oxidation of NADH at 0.0 V with a high sensitivity (8.7 mA/mM). These make PCC/OMC/GC electrode a promising candidate for stable and efficient electrochemical sensors for the detection of NADH.     

聚对氨基苯磺酸修饰电极对桑枝中桑色素的灵敏测定

采用电聚合的方法制备了聚对氨基苯磺酸(PABSA)修饰电极,以循环伏安法和差分脉冲伏安法研究了桑色素在该修饰电极上的电化学行为。PABSA和黄酮类药物桑色素的π-π共轭作用使得桑色素在该修饰电极上产生的氧化峰更加灵敏。实验发现,在pH 7.0的磷酸盐缓冲介质中,桑色素在0.214 V处产生灵敏的氧化峰。在优化实验条件下,采用差分脉冲伏安法对桑色素进行定量测定,桑色素的氧化峰电流与其浓度呈良好的线性关系,线性范围为5.0×10-7~1.0×10-3 mol/L,检出限为1.0×10-7 mol/L。将该修饰电极用于桑枝生物样品中桑色素含量的测定,结果满意。该方法具有灵敏度高、重现性好的特点,且该修饰电极稳定性高,可重复使用。