硬脂酸二茂铁酯L-B膜修饰SnO2电极的阻抗研究

测定了二茂铁衍生物——硬脂酸二茂铁酯L-B膜修饰SnO₂电极在Fe(CN)₆^3-/4-溶液中的阻抗性能,用单纯形法求出了等效电路中的元件参数值,计算了电极反应速度常数K_s。从分析SnO₂电极修饰不同层的硬脂酸二茂铁酯L-B膜的界面阻抗和电极反应的动力学性能,表明与在固相中研究的硬脂酸二茂铁酯L-B膜的阻抗性能明显不同,在Fe(CN)₆^3-/4-溶液中表现了电活性分子修饰电极的界面阻抗行为,进一步证实了修饰在SnO₂电极上的硬脂酸二茂铁酯L-B膜在Fe(CN)₆^3-/4-的氧化还原电极反应过程中,起电荷传递的中介作用。     

新型石墨烯-壳聚糖/二茂铁衍生物/细胞色素c修饰电极的制备及其用于亚硝酸钠的检测研究

具有共轭结构的分子导线是构筑分子电子器件的重要组成单元,而含有二茂铁单元的该类化合物具有良好的电化学性质,被广泛研究。基于此,本实验通过Sonogashira交叉偶联等反应合成了一种新型二茂铁乙炔衍生物( Fc-NH2),并经红外( IR)、核磁共振(1 H NMR和13 C NMR)、质谱( MS)和循环伏安( CV)等方法表征。利用Fc-NH2与石墨烯-壳聚糖( GH-CS)之间的相互作用制备了GH-CS/Fc-NH2复合物,并成功用于细胞色素c(Cytc)的固定,得到GH-CS/Fc-NH2/Cytc修饰电极。研究表明,GH-CS/Fc-NH2/Cytc/GCE在-0.2 V附近出现一对峰,对应于Cytc的可逆氧化还原峰。此电极对NaNO2有良好的电催化作用,在1×10-7~1.5×10-4 mol/L范围内,NaNO2浓度与氧化峰电流呈良好的线性关系,检测限低至4×10-8mol/L。此修饰电极不但可以实现细胞色素c的直接电化学,也可以用于定量检测NaNO2。     

新型双核二茂铁基席夫碱的合成及其电化学性质

乙炔二茂铁分别与对溴苯甲醛和对碘苯胺经Sonogashira反应制得中间体4-(2-二茂铁基-乙炔基)苯甲醛(2a)和4-(2-二茂铁基-乙炔基)苯胺(2b);2a和2b分别与对苯二胺和对苯二甲醛经胺醛缩合反应合成了两个新型的双核二茂铁基席夫碱类配合物(3a和3b),其结构经1H NMR和元素分析表征。电化学研究结果表明,3a(3b)的Epa,Epc,E1/2和ipc/ipa分别为0.279 V(0.311 V),0.195 V(0.196 V),0.238 V(0.260 V)和0.96(1.06);中间桥连基团对3的电化学性质影响显著。     

二硫键桥联双二茂铁芳胺修饰纳米金电极

对或间二茂铁苯胺与对-乙酰硫基苯甲醛反应得到两个席夫碱,硼氢化钠还原席夫碱碳氮双键的同时对乙酰硫基脱保护,合成了两个二硫键桥联双二茂铁芳胺类化合物,p-(Fc-Ph-NH-CH2-Ph-S)2和m-(Fc-Ph-NHCH2-Ph-S)2。将化合物自组装到电沉积纳米金的玻碳电极上,制得稳定的修饰电极,此电极在LiClO4的乙腈溶液中有一对氧化还原峰,用循环伏安法和交流阻抗谱法研究了修饰电极的电化学性质,化合物m-(Fc-PhNH-CH2-Ph-S)2修饰纳米金/玻碳电极对芦丁有催化氧化作用。     

二茂铁衍生物L—B膜修饰SnO2电极的性能

用外层单电子快速转移的氧化还原剂二茂铁及其衍生物修饰电极,在电极/溶液界面作为电子传递的中介物,可使电极上进行的慢反应得到加速、起中介催化作用。目前研究较多的是共价键合和高分子膜的修饰,其他方式的修饰报道不多。用能实现分子有序化排列的L-B膜技术进行氧化还原电活性分子的修饰电极还未见报道。我们用L-B膜技术在SnO_2电极上修饰了二茂铁的衍生物-硬脂酸二茂铁酯(FcOCOC_(17)H_(35))双亲化合物,曾研究了修饰膜的电化学可逆行为和稳定性。本文研究硬脂酸二茂铁酯L-B膜修饰的SnO_2电极     

β—环糊精与二茂铁包合物修饰碳糊电极上抗坏血酸的催？…

二茂铁及其衍生物不能牢固吸附于电极表面 ,特别是其氧化态 ( Fc+ )溶于水 ,影响了电极的稳定性 [1] .为解决这一问题 ,可采用合成有特殊官能团的二茂铁衍生物 [2 ] ,并利用 Nafion膜的双亲性将二茂铁固定于玻碳电极表面 [3]等方法 .这些方法制备的电极在使用过程中二茂铁仍会从电极表面缓慢流失 .我们利用二茂铁能与 β-环糊精形成 1∶ 1的包合物的性质[4] ,在乙二醇中制成了该包合物并掺杂于石墨粉中 ,用固体石蜡作粘合剂制成了 β-环糊精 -二茂铁包合物修饰碳糊电极 .首次把主客体包合物引入碳糊电极 ,大大改善了电极的性能 .该电极性能…     

新型二茂铁茚基化合物的设计、合成及电化学性质研究

利用Sonogashira偶联反应,以1,1¢-二碘二茂铁(I-C₅H₄FeC₅H₄-I),1,1¢-二碘联二茂铁(I-C₅H₄FeC₅H₄-C₅H₄FeC₅H₄-I)和2-乙炔茚(Ind-C≡CH)为原料,设计合成了6种新型二茂铁茚基化合物I-C₅H₄FeC₅H₄-C≡C-Ind(1,Ind为茚基), Ind-C≡C-C₅H₄FeC₅H₄-C≡C-Ind(2), I-C₅H₄FeC₅H₄-C₅H₄FeC₅H₄-C≡C-Ind(3), Ind-C≡C-C₅H₄FeC₅H₄-C₅H₄FeC₅H₄-C≡C-Ind(4), C₅H₅FeC₅H₄-C≡C-C₅H₄FeC₅H₄-C≡C-Ind(5), Fc-C≡C-C₅H₄FeC₅H₄-C₅H₄FeC₅H₄-C≡C-Ind(6,Fc为二茂铁基),其结构经¹H NMR, ¹³C NMR, MS(ESI)和X-射线单晶衍射表征,其中化合物1~3的晶体结构为首次报道。采用循环伏安法研究了化合物1~6的电化学性质。结果表明：取代基对调控二茂铁茚基衍生物二茂铁基之间的电子交互作用显著。单二茂铁茚基衍生物1和2中分别引入不对称和对称的共轭取代基团后,二茂铁基的氧化电位值升高。联二茂铁茚基衍生物3和4二茂铁基之间的电子交互作用基本不受取代基的影响。在乙炔桥相连接的取代二茂铁茚基衍生物5中,受金属-金属间距增加的影响,两个二茂铁基之间的电子交互作用减弱。不对称地引入二茂铁乙炔和乙炔茚取代基后,联二茂铁茚基衍生物6的两个二茂铁基之间的电子交互作用明显减弱。      

电化学聚合法制备二茂铁衍生物聚合膜电极

本文研究了二茂铁衍生物(α-羟乙基-,1,1’-二α-羟乙基-,乙酰基-,1,-二乙酰基-)在乙腈溶液及水溶液中的电化学行为.首次发现这类二茂铁金属有机化合物在电化学引发下发生电聚合反应,提出用电化学聚合制备其聚合物膜修饰电极的方法,并对聚合反应机理作了初步探讨.电化学聚合法简便快速,聚合过程可控,膜稳定且与电极的接着牢固,是一种很有实用意义的制备修饰电极的方法。     

硬脂酸二茂铁酯L-B膜的电化学性能研究

本文研究二茂铁衍生物——硬脂酸二茂铁酯(FcOCOC₁₇H₃₅)L-B膜技术修饰SnO₂电极的循环伏安性能.实验结果用电极表面吸附(修饰)分子的表面活度理论进行计算机拟合和此较,实验数据与理论符合较好.进一步求得修饰分子的标准电极电势和修饰量。结果表明硬脂酸二茂铁酯L-B膜电化学性能稳定,可逆性较好,可以作为快速电荷转移的修饰电极材料。     

二茂铁衍生物L-B膜在CdSe/Fe(CN)_6~((3-)/(4-))界面的中介催化作用

测定了CdSe薄膜电极及硬脂酸二茂铁酯L—B膜修饰后在Fe(CN)_6~(3-/4-)溶液中于白光和650nm单色光下的阻抗行为。用计算机非线性曲线拟合求出了等效电路中的元件参数值。进一步计算了CaSe薄膜电极光氧化还原反应速度常数。结果表明,修饰在CdSe薄膜电极上的硬脂酸二茂铁酯L—B膜在光诱发的CdSe/Fe(CN)_6~(3-/4-)界面电荷转移中加速电荷的传递起中介催化作用。     

Au/L-Met/GC电极的H2O2电催化氧化

在无额外的添加剂和保护剂的情况下,以柠檬酸钠还原氯金酸制得链状金纳米粒子,使用扫描电子显微镜（SEM）和透射电子显微镜（TEM）观察样品. 层层自组装技术可将金纳米粒子自组装,并分别以L-甲硫氨酸（L-Methionine,L-Met）、硫脲（Thiourea,TU）、丙烯基硫脲（Allyl thiourea,ATU）和聚乙烯吡咯烷酮（Polyvinylpyrrolidone,PVP）交联剂自组装于玻碳基底,即得金纳米粒子修饰电极. 以[Fe(CN)₆]^3-/4-氧化还原电对为探针,考察该修饰电极的电化学性质. Au/L-Met/GC电极有最佳电化学性能,循环伏安曲线和计时电流曲线测试表明,Au/L-Met/GC电极的H₂O₂电催化氧化有较高的灵敏度,线性范围2×10^-7 ~ 3×10^-3 mol·L^-1,检出限6.67×10^-8 mol·L^-1.     

Highly sensitive electrochemical determination of Sunset Yellow based on gold nanoparticles/graphene electrode

An electrochemical sensor was prepared using Au nanoparticles and reduced graphene successfully decorated on the glassy carbon electrode (Au/RGO/GCE) through an electrochemical method which was applied to detect Sunset Yellow (SY). The as-prepared electrode was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and electrochemical measurements. The results of cyclic voltammetry (CV) proved that Au/RGO/GCE had the highest catalytic activity for the oxidation of SY as compared with GCE, Au/GCE, and RGO/GCE. Differential pulse voltammetry (DPV) showed that the linear calibration curves for SY on Au/RGO/GCE in the range of 0.002 μM–109.14 μM, and the detection limit was estimated to be 2 nM (S/N = 3). These results suggested that the obtained Au/RGO/GCE was applied to detect SY with high sensitivity, low detection limit and good stability, which provided a promising future for the development of portable sensor in food additives.     

新型乙基溴硫磷印迹膜/纳米金化学修饰电极的研制及应用

以恒电位将金纳米粒子(AuNP)沉积于玻碳电极表面,在模板分子乙基溴硫磷存在下通过循环伏安法将L-半胱氨酸组装到金纳米粒子修饰的玻碳电极上,制备了可选择性识别乙基溴硫磷的L-Cys/ AuNP/ GCE印迹膜电极.结果表明,该电极具有良好的稳定性和重现性,对乙基溴硫磷的线性响应范围为2.5 ～17.5μmol/L,检出...     

维生素B_6在纳米Au-N,P/石墨烯修饰电极上的电化学行为

将金纳米粒子(AuNPs)电沉积在N,P/石墨烯(N,P/Graphene)修饰的玻碳电极表面,研究了维生素B_6(VB_6)在该修饰电极上的电化学行为。实验结果表明:VB_6在该修饰电极上出现一个良好的氧化峰,在最佳实验条件下,其氧化峰电流与VB_6的浓度在2.0×10~(-5)~4.0×10~(-4) mol/L范围内呈线性关系,相关系数R=0.998,检出限为9.2×10~(-6) mol/L。一些常见的物质如K~+、Na~+、Zn~(2+)、葡萄糖(Glu)不干扰VB_6的检测。此方法已用于片剂中VB_6含量的检测,获得较好结果。     

Electrochemical determination of nitrite using a gold nanoparticles-modified glassy carbon electrode prepared by the seed-mediated growth technique.

Seed-mediated growth of gold nanoparticles on glassy carbon (GC) surfaces was developed. The field emission scanning electron microscopy (FE-SEM) and electrochemical characterization confirmed the effective attachment of gold nanoparticles on GC surface with such a wet-chemical method. The as-prepared gold nanoparticles attached glassy carbon electrode (Au/GCE) presented excellent catalytic ability toward the oxidation of nitrite. Compared with bare GCE and planar gold electrode, the Au/GCE obviously decreased the overpotential of nitrite oxidation and improved the peak current. The catalytic current was found to be linearly proportional to the nitrite concentration in the range of 1 x 10(-5) - 5 x 10(-3) M, with a detection limit of 2.4 x 10(-6) M. The Au/GCE was successfully applied to the electrochemical determination of nitrite in a real wastewater sample, showing excellent stability and anti-interference ability.     

A sandwich-type DNA biosensor based on electrochemical co-reduction synthesis of graphene-three dimensional nanostructure gold nanocomposite films

A novel electrochemical DNA biosensor based on graphene-three dimensional nanostructure gold nanocomposite modified glassy carbon electrode (G-3D Au/GCE) was fabricated for detection of survivin gene which was correlated with osteosarcoma. The G-3D Au film was prepared with one-step electrochemical coreduction with graphite oxide and HAuCl₄ at cathodic potentials. The active surface area of G-3D Au/GCE was 2.629 cm², which was about 3.8 times compared to that of a Au-coated GCE under the same experimental conditions, and 8.8 times compared to a planar gold electrode with a similar geometric area. The resultant nanocomposites with high conductivity, electrocatalysis and biocompatibility were characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). A “sandwich-type” detection strategy was employed in this electrochemical DNA biosensor and the response of this DNA biosensor was measured by CV and amperometric current–time curve detection. Under optimum conditions, there was a good linear relationship between the current signal and the logarithmic function of complementary DNA concentration in a range of 50–5000 fM with a detection limit of 3.4 fM. This new biosensor exhibited a fast amperometric response, high sensitivity and selectivity and has been used in a polymerase chain reaction assay of real-life sample with a satisfactory result.     

A novel electrochemical sensor based on gold nanorods and Nafion-modified GCE for the electrocatalytic oxidation of nitrite

The high-quality CTAB-stabilized gold nanorods (Au NRs) were prepared by the way of seed-mediated protocol. The microstructure and composition of the Au NRs were identified by transmission electron microscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and UV–visible spectroscopy. Further, a novel non-enzymatic electrochemical sensor of nitrite based on Au NRs–Nafion-modified glassy carbon electrode (GCE) was successfully developed. Under the optimum experimental conditions, the electrochemical behaviors of nitrite on the Au NRs–Nafion-modified GCE were systematically studied by electrochemical impedance spectroscopy, cyclic voltammetry and chronoamperometry. The electrochemical investigations indicated that the Au NRs–Nafion-modified GCE had a wide linear range of 3.0 × 10^?6–6.0 × 10^?3 mol L^?1, an acceptable sensitivity of 130.9 ± 0.05 μA mM^?1 cm^?2, a fast response time of 3 s and a low detection limit of 0.64 ± 0.02 μmol L^?1 at the signal-to-noise ratio of 3 (S/N = 3). Additionally, the electrochemical sensor also showed good stability and favorable anti-interference capability for the detection of nitrite.     

The determination of adrenaline on the porous gold film modified glassy carbon electrode

A simple method has been developed to prepare porous Au film-modified glassy carbon electrode (PAu/GCE). By using a simple electrodeposition process, a dense porous Au (PAu) film possessing good adhesion, large surface area, and mechanical integrity, was obtained. The surface characterization studies confirm that the formation of porous film constituted of Au nanoparticles. It was found, from the CV studies, that the prepared PAu modified electrode shows excellent catalytic activity for the electro-oxidation of adrenaline (AD) in a neutral medium. As to the electrochemical response of redox of adrenaline/adrenalinequinone couple in 0.1 M pH 7.0 phosphoate buffer solution (PBS), at the PAu/GCE, the anodic peak potential E _pa shifted by 50 mV negatively in the negative direction, compared to that on the Au film modified glassy carbon electrode (Au/GCE), indicating the extraordinary activity of PAu in electrocatalysis for the oxidation process of AD. The application of the modified electrode for the determination of AD in pharmaceutical preparations indicates that the PAu/GCE has good sensitivity and reproducibility.     

Glucose biosensor based on new carbon nanotube-gold-titania nano-composites modified glassy carbon electrode

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.     

Selective Electroanalysis of Ascorbic Acid Using a Nickel Hexacyanoferrate and Poly(3,4‐ethylenedioxythiophene) Hybrid Film Modified Electrode

The mixed‐valent nickel hexacyanoferrate (NiHCF) and poly(3,4‐ethylenedioxythiophene) (PEDOT) hybrid film (NiHCF‐PEDOT) was prepared on a glassy carbon electrode (GCE) by multiple scan cyclic voltammetry. The films were characterized using atomic force microscopy, field emission scanning electron microscopy, energy dispersive spectroscopy, X‐ray diffraction, and electrochemical impedance spectroscopy (AC impedance). The advantages of these films were demonstrated for the detection of ascorbic acid (AA) using cyclic voltammetry and amperometric techniques. The electrocatalytic oxidation of AA at different electrode surfaces, such as the bare GCE, the NiHCF/GCE, and the NiHCF‐PEDOT/GCE modified electrodes, was determined in phosphate buffer solution (pH 7). The AA electrochemical sensor exhibited a linear response from 5×10⁻⁶ to 1.5×10⁻⁴ M (R²=0.9973) and from 1.55×10⁻⁴ to 3×10⁻⁴ M (R²=0.9983), detection limit=1×10⁻⁶ M, with a fast response time (3 s) for AA determination. In addition, the NiHCF‐PEDOT/GCE was advantageous in terms of its simple preparation, specificity, stability and reproducibility.