硝酸根离子选择性电极的构建及研究进展

硝酸盐含量的检测对于评价环境中硝酸盐污染和了解生态系统氮循环方面起着非常重要的作用。离子选择性电极因操作简单、选择性好、方便携带、价格低廉等优点被广泛应用于环境样品中硝酸根的测定。本文从离子选择性电极功能材料、电极设计和实际应用三方面阐述了近20年硝酸根离子选择性电极的研究进展,汇总了新合成硝酸根离子载体的选择性性能,从固体接触传导层和离子选择性敏感膜组分角度分析了固体接触式聚合物膜硝酸根离子选择性电极的构建机理,总结了非聚合物膜硝酸根离子选择性电极的发展,并对硝酸根离子选择性电极在环境中的典型应用进行了介绍,以期为水环境和土壤中硝酸根的测定提供技术支持。     

基于电流脉冲沉积法的硝酸根微传感器研究

基于微加工技术(Microfabrication technology)制备微传感电极并进行电化学表面修饰,研制出一种用于水体中NO#3浓度检测的电化学微传感器。微传感器以两电极传感芯片为信号转换部件,使用电流脉冲沉积法在铂质工作电极表面制备微观形貌呈枝簇状的铜质敏感材料,利用铜质材料对酸性溶液中NO#3的电催化还原特性,测量还原电流的大小,实现对NO#3浓度的检测。采用扫描电子显微镜(SEM)和X射线衍射分析(XRD)技术对敏感膜进行表征和监测,探索高活性铜质敏感膜的制备方法;使用微传感器对硝酸盐标准样品进行检测,在低浓度范围(12.5~200μmol/L),响应灵敏度为0.1422μA/(μmol/L);高浓度范围(200~3000μmol/L),响应灵敏度为0.0984μA/(μmol/L),均表现出较高的检测灵敏度;使用微传感器对北京等地的实际湖库水样进行检测,结果与专业水质检测机构采用紫外分光光度法的测试结果偏差在#3.9%~15.4%之间,两者具有一定的相关性,表明微传感器能够用于实际水样中NO#3浓度的测量。     

基于铜纳米簇的硝酸根微传感器的研究

基于循环伏安扫描(CV)的电化学沉积方法制备出多孔性纳米簇状结构铜膜,结合采用微机电系统(Micro electro mechanical systems,MEMS)技术制备的微电极芯片,研制出用于NO3-检测的安培型微传感器。考察该微传感器对NO3-的响应性能,在6.25~300mmol/L浓度范围内,灵敏度为0.0526mA/(mmol/L),线性度99.93%;在300~3500mmol/L浓度范围内,灵敏度为0.0353mA/(mmol/L),线性度99.18%。与文献报道相比,该传感器表现出更高的灵敏度。考察水体中常见的NO2-,Cl-,HPO42-/PO43-,SO42-,HCO3-/CO23-,Na+和K+等离子对该传感器的干扰性能,传感器表现出较好的抗干扰性能。采用该微传感器对实际水样进行测试,测试结果与具有权威资质的测试公司的测试结果之间具有一定的相关性。实验结果表明,采用循环伏安沉积方法在微电极表面制备的纳米簇状结构的铜敏感膜,比表面积大,催化活性高,对NO3-表现出了很好的敏感特性和选择性,适用于对微量NO3-的检测。     

基于钯金修饰超微叉指电极的土壤硝酸盐检测系统

针对土壤中硝酸盐快速检测的需求,研制了一种集成土壤浸出液获取和硝酸盐检测功能的土壤硝酸盐现场快速检测系统.硝酸盐检测采用钯金修饰的超微叉指传感电极.该传感电极采用微电子机械系统(MEMS)工艺制备,集成结构为叉指阵列分布的工作电极和对电极.硝酸盐敏感钯金复合膜采用恒压法制备,利用两种金属的协同作用提高硝酸盐检测的灵敏度...     

基于聚吡咯纳米线修饰玻碳电极的硝酸根电流型传感器研究

在玻碳电极表面,采用电聚合方法一步制备聚吡咯纳米线。由于聚吡咯的电化学氧化还原过程伴随有硝酸根的掺杂/脱掺杂,基于此构建了硝酸根电流型传感器。详细探讨了电聚合溶液的pH值、电聚合电位、电聚合时间、富集电位和富集时间对聚吡咯纳米线形貌,以及对硝酸根在修饰电极表面电化学响应的影响。在最佳条件下,构建的硝酸根传感器的线性范围为1.0×10-3～4.0×10-3 mol/L,检出限(S/N=3)达到2.2×10-4 mol/L,且具有良好的稳定性、重现性以及抗干扰能力。     

三维金纳米团簇/多壁碳纳米管-Nafion膜修饰电极的电化学制备及血红蛋白的直接电化学

用改进的全电化学三步法制备三维金纳米团簇/多壁碳纳米管(3D Au/MWCNTs)纳米复合材料,并用Nafion(Nafion)膜进行涂布固定,制得3D Au/MWCNTs-Nafion修饰电极.利用透射电子显微镜(TEM)和能量色散光谱(EDS)对所得纳米复合材料的形貌进行表征.3D Au/MWCNTs具有金纳米核团簇而成的特殊圆丘状三维结构,电化学活性表面积(ECSA)比均匀分散的Au/MWCNTs提高了一个数量级,可有效提高血红蛋白(Hb)在电极表面的负载量.运用循环伏安法和计时电流法对3D Au/MWCNTs-Nafion修饰电极的生物电催化性质进行研究,其在Hb溶液中显示了良好的电催化活性和稳定性:还原氧化峰电流高,反应可逆性好,提供了有利于Hb直接电子转移的电化学环境.固载于Au/MWCNTs-Nafion上的Hb能够保持其生物活性,对双氧水(H2O2)表现出良好的催化性能,这是3D Au纳米团簇和MWCNTs共同作用的结果.实验表明,3D Au/MWCNTs-Nafion修饰电极结构特殊、性能优越,对Hb的直接电化学研究具有积极的促进作用,为准确高效的检测Hb及相关生物活性物质提供了新的电极选择.     

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。     

基于金粒子修饰二硫化钼纳米复合材料的电化学发光免疫传感器的构建及其应用研究

生物标志物的快速、精准检测对控制和预防疾病或病毒的暴发具有重要意义.该研究将三维花状Au@(MoS2/GO/o-MWNTs)纳米复合物(AMGMs)作为一种理想的基底,利用"三明治"免疫夹心组装法构筑一种高灵敏的电化学发光免疫传感器,并用于前列腺特异性抗原(PSA)的高灵敏检测.AMGMs不仅具有良好的导电性和生物相容...     

Silver-Selective Electrode Based on a Direct Modified Electrode Silver Hexacyanoferrate(II) Film

ABSTRACT

A silver hexacyanoferrate(II) modified electrode is introduced as a silver-selective electrode. The electrode was prepared based on a new type of chemically modified electrodes by direct modification of the electrode surface. The electrode response characteristics were investigated by potentiometry. The calibration curve of the electrode shows a linear potentiometric response to Ag⁺ in the range of 10^-7 - 10^-2 M with detection limit of 5 × 10^-8. The modified electrode described in this paper is very simple, low cost and has linear response to Ag⁺ with a slope of 52-55 mV per decade.     

3D Dendritic Nanostructure of Silver‐Array: Preparation,Growth Mechanism and Application in Nitrate Sensor

A 3D dendritic nanostructure of silver‐array (DSA) was prepared via electrodeposition on an interdigitated array (IDA) microelectrode. For preparation of this nanostructure, the optimal parameters such as deposition potential, deposition time, the electrode bandwidth and gap size were systematically investigated. It was found that the edge effect of the IDA microelectrode is a key factor for controlling the 3D dendritic growth of silver. Furthermore, the formation of the 3D dendritic morphology was discussed from the aspect of electrochemical nucleation theory and nonequilibrium growth dynamics to give a deep understanding of its growth mechanism. For its potential practical application, we showed that the as‐prepared 3D DSA nanomaterial exhibited high electrocatalytic reduction ability to nitrate in neutral solution and excellent performance for nitrate determination. An amperometric nitrate microsensor based on the 3D DSA was obtained.     

Comparative Study on Electroanalysis of Fenthion Using Silver Amalgam Film Electrode and Glassy Carbon Electrode Modified with Reduced Graphene Oxide

Oxidation and reduction processes of the insecticide fenthion was comparatively investigated at a reduced graphene oxide modified glassy carbon electrode (RGO‐GCE) and a cyclic renewable silver amalgam film electrode (Hg(Ag)FE) using square wave stripping voltammetry (SWSV). The influence of pH and SW parameters was investigated. The linear concentration ranges were found to be 1 × 10⁻⁶ – 2 × 10⁻⁵ and 1 × 10⁻⁷ – 2 × 10⁻⁵ mol L⁻¹ for Hg(Ag)FE and RGO‐GCE, respectively. The detection and quantification limits were calculated as 1.3 × 10⁻⁷ and 4.5 × 10⁻⁷ mol L⁻¹ for Hg(Ag)FE and 7.6 × 10⁻⁹ and 2.5 × 10⁻⁸ mol L⁻¹ for RGO‐GCE. Both of the developed electroanalytical methods offer rapid and simple detection of fenthion and were used on spiked tap and river water and apple juice samples. Scanning electron microscopy was used for RGO‐GCE surface characterization.     

Potentiometric Immunosensor Based on Immobilization of Hepatitis B Surface Antibody on Platinum Electrode Modified Silver Colloids and Polyvinyl Butyral as Matrixes

A highly sensitive immunosensor based on immobilization of hepatitis B surface antibody (HBsAb) on platinum electrode (Pt) modified silver colloids and polyvinyl butyral (PVB) as matrixes has been developed for potentiometric immunoanalysis to detect hepatitis B surface antigen (HBsAg) in this study. HBsAb molecules were immobilized successfully on nanometer‐sized silver colloid particles associated with polyvinyl butyral on a platinum electrode surface. The modification procedure was electrochemically monitored by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The HBsAb‐silver‐PVB‐modified electrode exhibited direct electrochemical behavior toward HBsAg. The factors influencing the performance of the resulting immunosensor were studied in detail. More than 94.7% of the results of human serum samples obtained by this method were in agreement with those obtained by enzyme‐linked immunosorbent assays (ELISAs). The resulting immunosensor exhibited a sigmoid curve with log HBsAg concentration, high sensitivity (39.8 mV/decade), wide linear range from 16.0 to 800 ng mL^?1 with a detection limit of 3.6 ng mL^?1, fast potentiometric response (<3 min) and long‐term stability (>4 months). The response mechanism of the immunosensors was also studied with AC impedance techniques.     

银掺杂聚L-甲硫氨酸修饰电极同时测定对苯二酚和邻苯二酚

用循环伏安法制备了银掺杂聚L-甲硫氨酸修饰玻碳电极,研究了对苯二酚和邻苯二酚在该修饰电极上的电化学行为,建立了同时测定对苯二酚和邻苯二酚的新方法.研究发现,在pH=5.0的磷酸盐缓冲溶液中,扫速为100 mV/s时,对苯二酚和邻苯二酚在银掺杂聚L-甲硫氨酸修饰玻碳电极上均出现1对氧化还原峰,峰电位分别为:Epa=0.228 V、Epc =0.162 V和Epa=0.347 V、Epc =0.287 V,二者的氧化峰电位差达119 mV,还原峰差达125 mV.在最佳的条件下,用差分脉冲伏安法同时测定邻苯二酚和对苯二酚的线性范围为3.00 ×10-6～1.00 ×10-4mol/L,检出限为8.0×10-7 mol/L(对苯二酚)和5.0×10-7 mol/L(邻苯二酚).此法用于废水样中对苯二酚和邻苯二酚的测定,获得满意结果.     

基于2,3-丁二酮双缩氨基硫脲为中性载体的新型银离子选择性电极的研究

研究了基于2,3-丁二酮双缩氨基硫脲为中性载体的聚氯乙烯(PVC)膜电极, 该电极对银离子(Ag^＋)具有优良的电位响应性能. 在pH＝3.0的NaOH-HNO₃体系中, 该电极对Ag^＋电极电位呈现近能斯特响应, 线性响应范围为3.0×10^－6～1.0×10^－2 mol/L, 斜率为52.6 mV/decade (20 ℃), 检测下限为1.0×10^－6 mol/L. 相对于常见的阳离子, 该电极对Ag^＋表现出良好的选择性. 采用交流阻抗技术研究了电极响应机理, 并将电极初步应用于回收率实验, 结果令人满意.     

聚对甲苯胺修饰电极的研制及其PH特性的研究

本文叙述了聚对甲苯胺修饰电极的制备及其电化学响应特性。在ＰＨ２－１３范围内电极电位与ＰＨ有良好的线性关系，电极响应应快，导电性能良好，抗干扰性能强，不受氧化还原物物质影响。用于测定饮料、湖水的ＰＨ值，结果与玻璃电极测定值基本相符。     

Study on Lead Dioxide Modified Electrode and Its Application in Detection of Phenols

IntroductionOflate,thereisagreatinterestintheimprovementofleaddioxideasananodematerialforelectrosynthesis,ozonegenerationandwastewatertreatmentowingtoitshighelectri calconductivity ,largeoxygenoverpotentialandchemicalin ertness.1 5PbO2 canbeobtainedasanodicdepositsfromsolu tionsofthelow valenceions,basicstudiesontheseelec trodesaremainlyconfinedtothenucleationgrowthprocessofleaddioxidecrystallites ,ormodifiedbyothercationsinordertoimproveitsproperties.6 However,itselectrocatalyticactivi tydepe…     

A Novel Method of High Sensitive Determination of Prednisolone on Renewable Mercury Film Silver Based Electrode

Fast and sensitive method of prednisolone determination at renewable mercury film electrode using differential pulse adsorptive stripping voltammetry (DPAdSV) was successfully developed. The effects of various factors such as: preconcentration potential and time, pulse height, step potential and supporting electrolyte composition were optimized. A linear voltammetric response for analyte was obtained in the concentration range from 0.05 µmol L⁻¹ (18 µg L⁻¹) to 2.25 µmol L⁻¹ (0.81 mg L⁻¹), with a detection limit of 0.01 µmol L⁻¹ for preconcentration time of 20 s. Repeatability of method was determined as RSD % for prednisolone concentration of 0.04 µmol L⁻¹ as 1.6 % (n=9). The proposed method was successfully applied and validated by recovery parameter of prednisolone in simulated sample and pharmaceutical product.     

18－冠－6修饰碳糊电极测定金的研究

本文研究了１８－冠－６修饰碳糊电极测定金的条件，金在０．５ｍｏｌ／ＬＨＣ１－０．００５ｍｏｌ／ＬＫＣ１底液中富集，介质交换到０．０１ｍｏｌ／ＬＨＣ１中进行测定。金（Ⅲ）浓度在０．１～１．０μｇ／ｍＬ范围内呈线性关系，相对标准偏差为９．７％，检出限为２０ｎｇ／ｍＬ。可不经预先分离直接测定矿样中的金，结果良好。并研究了Ａｕ（Ⅲ）在１８－冠－６碳糊修饰电极上的还原机理。