DNA在Mg/聚2,6-吡啶二甲酸膜上的固定和杂交及其PAT基因片段的电化学阻抗谱测定

以静电吸附法使Mg²⁺修饰于玻碳电极(GCE)上电聚合的2,6-吡啶二甲酸膜(PDC)上, 制得的Mg/PDC/GCE电极, 成为DNA固定及杂交的良好平台. 应用微分脉冲伏安法和电化学阻抗谱对DNA的固定和杂交进行表征. 以电化学阻抗谱免标记法检测目标DNA比以亚甲基蓝为指示剂的微分脉冲伏安法有更高的灵敏度. 固定于电极表面的DNA探针与互补单链DNA杂交后使电负性的[Fe(CN)₆]^3-/4-的表面电子传递电阻值显著增大, 以此作为检测信号可以高灵敏度地测定目标DNA. 电化学阻抗谱检测转基因植物外源PAT基因片段, 线性范围为1.0×10^-9 ~ 1.0×10^-5 mol/L, 检测限为3.4×10^-10 mol/L.     

基于纳米银/碳纳米纤维复合材料的增强效应电化学测定多贝斯

将银纳米粒子(AgNPs)电沉积在碳纳米纤维(CNFs)修饰玻碳电极表面制备纳米银/碳纳米纤维修饰玻碳电极(AgNPs/CNFs/GCE).采用扫描电镜考察其表面形态,在K3[Fe(CN)6]-K4[Fe(CN)6]体系中用循环伏安法和电化学阻抗法研究AgNPs/CNFs/GCE的电化学行为.采用循环伏安法和方波伏安法...     

铂微粒修饰碳纳米管-纳米TiO2/聚苯胺复合膜电极的制备及其电化学性能

采用循环伏安法,在200 mmol.L-1苯胺与500 mmol.L-1H2SO4的混合溶液中,在-0.1 V~0.9 V扫描(50 mV.s-1),实现了苯胺在碳纳米管-纳米TiO2膜电极上的电化学聚合,得到翠绿色的聚苯胺膜(PANI),并用交流阻抗谱对PANI的电化学性质进行了表征。在PANI电极上修饰铂,制得铂微粒修饰PANI电极(PANI-Pt)。研究发现PANI-Pt对抗坏血酸的氧化有很高的催化活性。     

膜电阻对自组装膜修饰电极电化学行为的影响

应用循环伏安和交流阻抗技术研究了 16烷基硫醇自组装膜修饰的金电极在Fe(CN) 63 - /Fe(CN) 64 - 溶液中的电化学行为 .无“针孔”缺陷的自组装膜对溶液与基底间的界面电子转移具有强烈的阻碍作用 ,当过电位较大时 ,In(I/ η)对 η1/2 之间具有良好的线性关系 .通过对Au/SAM /Hg模拟体系的电流———电压曲线进行测定 ,得到了自组装膜膜电阻的特征 .指出由于膜电阻的存在 ,自组装膜修饰电极在Fe(CN) 63 - /Fe(CN) 64 - 溶液中的行为实质上反映了膜自身的电阻特征     

碳纳米管修饰电极分子印迹传感器的制备及其对氧乐果的测定

以氧乐果为模板分子,邻苯二胺为功能单体,在碳纳米管修饰的玻碳电极表面通过电聚合方法制成氧乐果分子印迹聚合物膜,用无水乙醇洗脱后制备出对氧乐果有特异响应的电化学传感器。通过循环伏安法和电化学阻抗法对分子印迹传感器的电化学性能进行表征。以K_3Fe(CN)_6为探针,采用差分脉冲伏安法研究了该分子印迹传感器的分析性能,建立了氧乐果的间接测定方法。结果表明,K_3Fe(CN)_6的相对峰电流与氧乐果浓度在1.0×10~(-7)~2.0×10~(-6)mol/L范围内呈良好的线性关系,检出限为3.6×10~(-8)mol/L。     

电化学组装法制备对-巯基苯胺/聚苯胺纳米有序导电聚合物膜

提出了制备二维纳米有序有机导电聚合物膜的新方法--电化学组装法,应用该方法在电位脉冲的作用下使苯胺聚合到对-巯基苯胺修饰的金电极上,获得了致密、有序的对-巯基苯胺/聚苯胺(p-aminothiolphenol/polyaniline,PATP/PANI)导电寡聚物薄膜.用STM研究了Au(111)/PATP、Au(111)/PATP/PANI膜表面的二维有序性,用SERS谱表征了Au(粗糙表面)/PATP、Au(粗糙表面)/PATP/PANI膜的结构和成分,并以[Fe(CN)₆]^3-/[Fe(CN)₆]^4-为探针研究了其电子传递性能.结果表明用电化学组装法制备的PATP/PANI膜在纳米尺度上是二维有序的,且具有良好的电子传递性能.     

阳离子选择性膜修饰Ir/IrO_x-pH电极增敏作用研究

采用阳离子选择性透过膜对Ir/IrOx-pH电极表面进行修饰,提高了电极抗阴离子氧化/还原性物质的干扰能力.利用SEM观察离子选择性透过膜的表面孔径分布;通过循环伏安法研究了氧化物电极在Fe(CN)63- 溶液中的电化学行为.实验表明,选择性透过膜对电极的E-pH线性、准确度、响应时间等无影响,显著改善了电极在含氧化/还原性物质中的使用性能.从而提高了电极的抗干扰能力和灵敏度.     

多巴胺在dsDNA/Ni2+/聚邻氨基酚修饰碳糊电极上的伏安行为

通过电化学聚合法在碳糊电极上共聚制备了聚邻氨基酚/Ni2+膜(Ni2+/P-OAP/CPE), 研究了膜的伏安特性, 并制成dsDNA修饰电极, 通过电化学和紫外光谱法进行表征. 将dsDNA/Ni2+/P-OAP/CPE电极应用于多巴胺的电催化氧化, 同时将该方法用于盐酸多巴胺针剂的测定, 亦获得了满意的结果.     

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...     

聚邻氨基苯甲酸-铜复合薄膜修饰电极的制备及其电化学性能

利用聚合物官能团对金属离子的配位作用,在电极表面原位制备了金属粒子。 首先在玻碳电极（GCE）表面电沉积聚邻氨基苯甲酸(PoABA),再化学吸附铜离子(Cu2+),用水合肼还原得到单质铜(Cu0)。 采用扫描电子显微镜和能谱分析表征了聚邻氨基苯甲酸 铜(PoABA-Cu0)复合薄膜的表面形貌和元素构成,研究了PoABA-Cu0修饰电极的电化学性能,并以其检测了过氧化氢（H2O2）。 结果表明,电极表面被修饰上了一层PoABA-Cu0复合薄膜;制备的修饰电极对H2O2具有良好的电催化性能,在邻氨基苯甲酸的聚合圈数为10、Cu2+的吸附时间为10 min、工作电压为-0.3 V时,该修饰电极对H2O2表现出了最佳的检测性能,其线性浓度范围为5.0×10-5～1.0×10-2 mol/L,灵敏度为96.3 μA·L/(mmol·cm),检测限为5.0×10-5 mol/L,且具有较好的稳定性。     

氯化钯掺杂的羧基丁苯胶乳薄膜的制备及用于化学镀铜性能

利用羧基丁苯胶乳优良的成膜性能,并通过氯化钯掺杂使薄膜具备催化化学镀的活性,在其表面进行化学镀铜研究,选用次亚磷酸钠和硼氢化钠为还原剂,将硫酸铜还原成单质铜。 采用扫描电子显微镜（SEM）、能量色散谱（EDS）和X射线衍射（XRD）等对其形貌、成分进行表征。 测试了胶膜的增重率、表面金属及沉积层的结合牢度。 结果表明,薄膜的表面形成均匀致密、导电性优良和结合力良好的铜层。 该方法可应用于平面非金属材料如聚酯透明材料、装饰板材等,获得了良好导电表面,形成具有电磁屏蔽功能的面型材,具有广阔应用前景。     

CuInSe_2薄膜的电化学沉积及其形成机理

采用电化学沉积法制备了太阳电池用CuInSe2薄膜.利用循环伏安法(CV)、X射线能谱(EDS)和X射线衍射技术(XRD)研究了电沉积过程中CuInSe2的形成机理,并研究了制备工艺对膜层成分、形貌和物相结构的影响.研究结果表明,铟进入固相是通过In3+受Cu3Se2诱导作用欠电势还原或者In3+与H2Se反应这两种途径实现;先沉积的Cu3Se2与新生成的铟或铟硒化合物反应最后生成CuInSe2.在阴极电位为-0.58~-0.9 V(vs.SCE)时出现了不随电位变化的极限还原电流,在该电位范围内进行电沉积获得了化学计量组成稳定可控且相对致密平整的CuInSe2薄膜.电沉积的CuInSe2薄膜经真空退火处理后结晶质量得到明显改善.     

水溶液中Mn2+对硫化锌纳米粒子形貌的调控作用

利用硫代乙酰胺在水溶液中缓慢释放的S2-与Zn2+反应制备了ZnS纳米颗粒,ZnS纳米颗粒沉积吸附在3-磺酸基丙基三甲氧基硅烷自组装单层膜上。 实验发现,溶液中添加少量Mn2+,可以显著影响ZnS纳米颗粒的形貌,对ZnS纳米晶的生长方向也有重要影响。 EDS和XRD谱证实Mn2+并没有掺杂到纳米颗粒中去。 这为纳米粒子形貌的调控提供了新途径。 并对ZnS的形成过程进行了探讨,并提出了可能的影响纳米材料形貌的机制。     

Spacer layer screening effect: a novel fluorescent film sensor for organic copper(II) salts

A fluorescent film sensor was prepared by chemical assembly of pyrene on a glass plate surface via a long flexible spacer. It was found that the film is highly selective for some organic Cu2+ salts, such as copper acetate and copper propionate. The presence of inorganic Cu2+ salts and other metal(II) acetates, including Ni2+, Co2+, Pb2+, Cd2+, Zn2+, etc., had little effect upon the sensing behavior of the film for copper acetate or copper propionate. The observation was explained by employing a proposed "two-dimensional solution" model. The quenching by copper acetate of the emission of the film is static in nature due to complexation of the spacers to the metal ions. Furthermore, the response of the film sensor to copper acetate is fully reversible. To the best of our knowledge, this film sensor may be the first one that can differentiate greasy copper salts from inorganic copper salts.     

对苯二酚在掺Cu(Ⅱ)类普鲁士蓝膜修饰电极上的电化学行为研究

采用循环伏安法在普鲁士蓝膜中掺杂Cu2+,制得掺Cu(Ⅱ)类普鲁士蓝膜(Cu-PB膜)。利用循环伏安法、库仑分析法和电化学阻抗法对Cu-PB膜进行电化学表征,结果显示Cu2+进入普鲁士蓝的内部结构,取代了其中的高自旋铁。该Cu(Ⅱ)类普鲁士蓝膜对对苯二酚具有明显的电催化作用,电极反应过程是扩散控制的准可逆过程,在5.0×10-5~1.0×10-3mol.L-1范围内,还原峰电流与对苯二酚浓度呈良好的线性关系,检出限为1.0×10-6mol.L-1。计算了对苯二酚在Cu-PB膜修饰电极上电极过程的动力学参数。     

PANI-SnP复合膜电极在镍镉废水中电控离子交换性能

采用滴涂法在铂基底制备了电活性聚苯胺-磷酸锡(PANI-SnP)复合膜电极,考察了该电极在Ni²⁺、Cd²⁺溶液的电控离子交换性能. 用傅立叶变换红外光谱和扫描电镜分析观察复合膜的组成及表面形貌;在0.1 mol·L^-1 Ni(NO₃)₂、Cd(NO₃)₂溶液,通过循环伏安法比较了PANI膜、SnP膜及PANI-SnP复合膜电极的电化学性能,并结合电化学石英晶体微天平技术重点考察了PANI-SnP复合膜的离子交换机制;同时,通过循环伏安法调控复合膜电极的氧化还原电位,结合X射线能谱和X射线光电子能谱分别测定了其氧化和还原状态的元素组成. 结果表明,PANI-SnP复合膜电极在Ni²⁺、Cd²⁺溶液均有良好的氧化还原电活性和可逆离子交换性能,其Cd²⁺离子选择性优于Ni²⁺离子,通过电控离子交换可使Cd²⁺离子从镍镉废水高效分离.     

Removal of Cu2+ from aqueous solution by chitosan-coated magnetic nanoparticles modified with alpha-ketoglutaric acid

Chitosan-coated magnetic nanoparticles (CCMNPs), modified with a biodegradable and eco-friendly biologic reagent, alpha-ketoglutaric acid (alpha-KA), was used as a magnetic nanoadsorbent to remove toxic Cu(2+) ions from aqueous solution. The prepared magnetic nanoadsorbents were characterized by FTIR, TEM, VSM, XRD, and EDS. Factors influencing the adsorption of Cu(2+), e.g., initial metal concentration, initial pH, contact time and adsorbent concentration were investigated. TEM images show that the dimension of multidispersed circular particles is about 30 nm and no marked aggregation occurs. VSM patterns indicate superparamagnetic properties of magnetic nanoadsorbents. EDS pictures confirm the presence of the Cu(2+) on the surface of magnetic nanoadsorbents. Equilibrium studies show that Cu(2+) adsorption data follow Langmuir model. The maximum adsorption capacity (q(max)) for Cu(2+) ions was estimated to be 96.15 mg/g, which was higher than that of pure CCMNPs. The desorption data show no significant desorption hysteresis occurred. In addition, the high stability and recovery capacity of the chitosan-coated magnetic nanoparticles modified with alpha-ketoglutaric acid (alpha-KA-CCMNPs) suggest that these novel magnetic nanoadsorbents have potential applications for removing Cu(2+) from wastewater.     

Determination of copper in water and plant samples by flame atomic absorption spectrometry after preconcentration on octadecyl silica membrane disks modified with a recently synthesized Schiff's base

A simple, selective, reliable, and sensitive method for the determination of trace amounts of CU2+ ions in aqueous samples is proposed. The Cu2+ ions are adsorbed quantitatively during the passage of aqueous samples through an octadecyl (C18) silica membrane disk modified by a symmetrical tetradentate Schiff base ligand, N,N'-bis(4-phenylazo salicylaldimine) 3-chloro-1,2-phenylenediamine (H2L). The retained Cu2+ ions were then stripped from the disk by elution with the minimal amount of nitric acid solution and determined by flame atomic absorption spectrometry. Various parameters, such as the effect of pH, flow rate, type and amount of eluent, and the effects of various cationic interferences on the recovery of ions were studied. The proposed method permitted large enrichment factors (about 550 and higher). The limit of detection of the method was 1.5 x 10(-2) microg/L. The use of the same disk modified with 6 mg H2L for at least 30 times showed no change in the recovery of Cu2+ ions. The accuracy of the method was confirmed by determination of Cu2+ ions in standard samples [National Institute of Environmental Studies (NIES) No. 2 and Nippon Keikinzoku Kogyo (NKK) No. 920]. The results demonstrated good agreement with certified values.     

Copper(II) ion-selective microelectrochemical transistor

A device has been developed for the measurement of copper(II) ions (Cu²⁺) in aqueous medium. The device reported here is an electrochemical transistor which consists of two platinum electrodes separated by 100 μm spacing and bridged with an anodically grown film of polycarbazole. Polycarbazole film (undoped form) is observed to be highly selective for the Cu(II) ions. In a completed device, the conductivity of the polycarbazole film changes on addition of Cu(II) ions. The change in conductivity is attributed to the conformational changes in the polymer phase on occupation of the Cu(II) ions, without affecting electron/proton transfer. The device turns on by adding 2.5 × 10⁻⁶ M Cu(II) ions and reaches a saturation region beyond 10⁻⁴ M Cu(II) ion concentrations. In the above concentration range, the device response [I _D vs. log Cu(II) ion concentration] is linear. The selectivity of the device for other metal ions such as Cu(I), Ni(II), Co(II), Fe(II), Fe(III), Zn(II) and Pb(II) is also studied. Received: 6 April 1999 / Accepted: 20 August 1999