双柱碳纤维微电极的研究及其在测定多巴胺中的应用

报道了双柱微电极的制作方法,提出了用双柱碳纤维微电极在抗坏血酸存在下选择性地测定多巴胺.探讨了电极反应机理.多巴胺的浓度在5.0×10^-4～5.0×10^-6mol/L范围内与收集电流成正比.抗坏血酸浓度<5.0×10^-4mol/L时对测定结果无影响.     

一种用于多巴胺实时检测的集成微电极的微流控芯片

设计并制作了一种用于多巴胺实时检测的集成微电极的微流控芯片。芯片由一片聚二甲基硅氧烷( PDMS)沟道片和一片玻璃电极片组成,在PDMS沟道片上集成了用作细胞培养室的主通道和用于培养基输送的两条侧通道,在玻璃电极片上集成了用于多巴胺实时检测的微电极。为了解决PDMS沟道片与硅模具之间的脱模困难问题,研究了一种新的脱模方法。建立了一种Au-Au-Au三电极体系,表现出了良好的电化学检测性能。以溶解在神经干细胞培养基中的多巴胺为测试样品,对芯片的性能进行了初步研究。多巴胺的检出限为3.92μmol/L,线性检测范围为10~500μmol/L,片间的检测重复精度小于4%。     

离子选择性微电极阻抗转换器的研制

离子选择性微电极是测量生物细胞中离子活度的新型工具。近年来,已研制成了多种离子的PVC液膜微电极。微电极的尖端直径小至1微米,甚至0.1微米,电极的内阻高达10~(11)Ω以上。因此需要非常良好的绝缘及高输入阻抗的测试仪器。国产FW-1型微电极放大器的输入阻抗为10~(12)Ω,还不能同10~(10)Ω以上的微电极配合使用。为了提高微电极的测量精度,本工作研制了微电极阻抗转换器。该转换器的输入阻抗为10~(14)Ω,输出阻抗小于1Ω。设计中采用特殊的电源自举电路,使工作电压浮动,大辐度提高了输入     

人血白蛋白对钙离子选择性微电极测定的影响

应用离子选择性微电极作生物体组织内的测定时,必须要了解生物体体液中成分对电极可能产生的影响。我们用钙离子选择性微电极测定了在生理浓度范围内人血清白蛋白存在下对钙离子选择性微电极测定的影响,获得了较好的效果。     

石墨烯基微电极的制备及其在电化学传感中的应用

微电极由于灵敏度高、响应快、样品用量少、操作简便等特点,近年来在化学分析、生物医学、食品安全、环境检测等领域引起人们的广泛关注。 石墨烯具有超高的比表面积、优异的电子迁移率及良好的生物相容性等优点,近年来在电化学传感领域展示出巨大的发展前景。 本文围绕石墨烯基微电极的制备及其在电化学传感中的应用展开,总结了近年来国内外同行基于石墨烯修饰微电极和石墨烯微电极在重金属离子、多巴胺、葡萄糖、H₂O₂等分子检测方面取得的研究成果。 同时探讨了石墨烯基微电极在电化学传感方面面临的挑战和发展前景。     

聚L-组氨酸修饰碳黑微电极的制备及多巴胺的测定

用电聚合法制备了聚L-组氨酸修饰碳黑微电极,研究了多巴胺在该修饰电极上的电化学行为。实验表明:该修饰电极对神经递质多巴胺的电化学氧化有显著的催化作用,采用二次导数线性扫描伏安法对多巴胺进行测定,在pH 7.0的磷酸盐缓冲溶液中,多巴胺在0.15 V处产生一灵敏的氧化峰,多巴胺的氧化峰电流与浓度在4.0×10-8~1.0×10-4mol/L范围内呈线性关系,检出限(3σ)为1.0×10-8mol/L。该聚合物修饰电极具有良好的选择性,能有效地排除抗坏血酸对测定的影响,用于人工合成样品的分析。     

影响离子选择性微电极膜电阻的因素

离子选择性微电极的尖端直径可小至1μm以下,其内阻可达10~(11)Ω,因此,在应用中,需要高输入阻抗的测试仪器与其配合。一些作者从提高测试仪器的输入阻抗上作了努力;也有作者从微电极形式上作了改进,降低内阻及缩短响应时间。对于影响微电极内阻的因素,尚未见到较完整的报道。本文较详细地探讨了微电极形状、敏感膜中PVC和增塑剂及活性物质的含量、温度等几个主要因素对微电极内阻及性能的影响。本工作对提     

纳米TiN修饰平面微电极阵列在神经信息双模检测中的应用

采用氮化钛(TiN)修饰平面微电极阵列(pMEA),对其性能进行改进,开展了离体神经电生理和神经递质电化学的检测研究。采用磁控溅射法在实验室自制微电极阵列上修饰具有纳米结构的TiN材料,修饰后的微电极阻抗降低近一个数量级,背景噪声基线降至±6μV,信噪比是修饰前的1.7倍。在SD大鼠离体脑片神经电生理信号检测中,信噪比可达10∶1,能分离提取±12μV的微弱信号。神经递质多巴胺电化学信号检测下限达50 nmol/L(信噪比2∶1),浓度在0.05~100μmol/L内与电流响应的线性相关系数为0.998。实验结果表明,在微电极表面修饰纳米TiN,降低了微电极阻抗,提高了信噪比,实现了对神经信息微弱信号的检测。     

SEM-K1型钾微电极的研制

离子选择性微电极可直接插入生物体内测定细胞体液的成分及其变化,近年工作进展较快,国内尖端直径达微米级的微电极的研制工作尚未见报导^[1]。     

基于三维纳米银修饰电极的硝酸根微型传感芯片研究

研制一种基于金叉指微电极阵列(IDA)的电流型硝酸根离子(NO-3)微传感电极芯片.基于微机电系统(Micro-Electro-Mechanical Systems,MEMS)工艺制备金IDA微电极,通过电化学沉积技术在IDA微电极表面修饰三维枝状结构纳米银敏感膜,利用敏感膜对硝酸根离子良好的电催化还原性能,采用脉冲方波伏安(SWV)电化学测量方法,实现对硝酸根离子在25～1000μmol/L浓度范围内的快速检测,灵敏度达9.5 nA/(μmol/L),线性度为99.98%,检测下限为10μmol/L.考察水体中常见的NO-2,F-,3PO 4-,SO 42-,2CO3-,NH+4,Na+和K+等离子对该传感芯片的干扰性能,传感芯片表现出较好的抗干扰性能.制备的三维枝状结构纳米银修饰IDA微电极可实现水环境(pH 5.0～9.0)中NO-3的电化学检测,对应用于自然水环境中硝酸根离子的现场检测具有积极意义.     

组织胺敏感离子选择性微电极及其应用

合成了四对三氟甲基苯硼酸钠和三氟甲基苯硼－组织胺离子缔合牧，以该离子缔合物为对组织胺敏感的电活性物，进行了组织胺离子选择性的研究，同时制备了对 敏感的双通道离子选择性 电极，并对电极进行了考核。     

过氧化聚吡咯膜修饰微电极的制备及其电化学特性

用电聚合法在铂微盘电极上制备了聚吡咯膜，并将其在电解质水溶液中进行了过氧化处理。所得到的过氧化膜是非电子导体而为离子导体，膜具有多孔笥的特征。该膜具有排有离子的作用，而对大阳离子如多巴胺具有高度的选择性。     

Preparation of selective micro glucose sensor without permselective membrane by electrochemical deposition of ruthenium and glucose oxidase

A carbon fiber microelectrode, surface of which ruthenium and glucose oxidase (GOx) were electrochemically codeposited, has been investigated. The Ru deposition onto the microelectrode increased current response to H₂O₂ oxidation, while decreased oxidation currents due to interfering substances, such as ascorbic acid, uric acid, p-acetamidophenol, l-cysteine and dopamine. The codeposition of Ru and GOx gave further suppression of the interfering signals with keeping the current response to H₂O₂. When amperometric glucose sensing was conducted by using the GOx and Ru modified microelectrode, an increase in GOx concentration in the deposition bath enlarged oxidation current of H₂O₂ generated from glucose oxidation by GOx. The presence of ascorbic acid in analyte gave no error in detection of glucose and errors caused by uric acid was +3% at the most for measuring 5 mM glucose, which is the normal physiological level in blood.     

锂离子选择性微电极在生物体液中的响应

最近几年已报道了几种锂离子选择性电极.本文作者曾研制了以苯基膦酸二辛酯(DOPP)为溶剂,四苯硼酸盐为活性物质的PVC膜锂离子选择电极.本文在此基础上研制了锂离子选择性微电极,比较了以四苯硼酸钾(KTPB)及四苯硼酸钠(NaTPB)为活性物质的锂微电极的性能.同时考察了微电极在细胞内液、血清及生理盐液中对锂离子的响应特性.     

Fabrication and characterization of boron doped diamond microelectrode arrays of varied geometry

Boron doped diamond (BDD) is a well-known electrode material that exhibits an excellent electrochemical potential window with very low background current. With this, microelectrodes and microelectrode arrays (MEAs) have been found to even further lower background currents without compromising sensitivity. As such, BDD MEAs are excellent electrode materials for a variety of electroanalytical applications, capable of multi-mode detection. We fabricated BDD MEAs adapting traditional semiconductor microfabrication processes; the resulting MEAs were patterned in different geometries to find an optimum electrochemical response, depending on the application. This is demonstrated using 4 different MEA geometries of different size and spacing using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), where the charge transfer resistance (R_ct) increases as the electrodes are farther spaced from one another. Excellent sigmoidal voltammogram shape in CV was obtained for each BDD MEA geometry. BDD MEAs spaced farther from one another were found to give better resolution from the background in fast scan cyclic voltammetric measurements of dopamine due to the decrease in the double layer capacitance (C_dl) as verified with EIS. This work furthers the understanding of BDD MEAs and their pertinence to sensitive electroanalytical techniques.     

Development of a Pt modified microelectrode aimed for the monitoring of ammonium in solution

The development of selective and sensitive analytical methods for ammonium detection is important for the evaluation of the environmental effects of water pollution and the understanding of nitrogen cycling in ecosystems. In the current study, a new Pt nanoparticle microelectrode with high selectivity, sensitivity, accuracy and anti-interference capacity was successfully prepared for the quantitative measurement of ammonia concentration in artificial and real wastewater samples. The prepared Pt nanoparticle microelectrode had a selectively electrochemical catalytic oxidation activity for ammonium. Ammonium oxidation peak current presented a linear correlation with ammonium concentrations in artificial and real wastewater samples. Ammonium response was 92% of the initial value after 120 measurements, indicating that the prepared microelectrode is reliable and stable as an ammonium sensor. The lifetime of the modified microelectrode was of at least 150 days at room temperature and of at least 500 repetitive measurements. The present method is a simple way of preparing an ammonium sensor with very good reproducibility. Moreover, the proposed electrochemical method has been validated by comparing the obtained results of the analysis of ammonium in artificial and real wastewater samples with those obtained from spectrophotometry.     

间苯二酚杯[4]芳烃为涂层的压电石英传感器测定液相多巴胺

研究了以间苯二酚杯[4]芳烃为敏感涂层的石英压电晶体（PQC）传感器,在中 性磷酸盐缓冲液体系中对神经传递质多巴胺和抗坏血酸的响应,发现间苯二酚杯 [4]芳烃对多能上能下胺有很好的响应选择性,这归因于间苯二酚杯[4]芳烃与多巴 胺分子结构相匹配,形成主客体超分子体系。以间苯二酚杯[4]芳烃为涂层的POC传 感器对液相中多巴胺具有响应快、重现性好、灵敏度高的特点,线性响应范围为3. 5-500 μg/g。     

CuNi/β-环糊精/还原氧化石墨烯修饰电极电化学检测多巴胺

建立了一种循环伏安法制备CuNi/β-环糊精/还原氧化石墨烯修饰玻碳电极(CuNi/β-CD/ERGO/GCE)的方法。通过多巴胺在该修饰电极上的电化学行为发现,该电化学传感器实现了快速、灵敏的测定多巴胺。该传感器用差分脉冲伏安法(DPV)测定多巴胺时,其电化学响应电流与多巴胺浓度在0.01~20μmol/L之间呈线性关系,检测限为8 nmol/L。该传感器用于尿液样品中的多巴胺检测,回收率在95.6%~107.2%之间。     

Selective detection of extracellular glutamate in brain tissue using microelectrode arrays coated with over-oxidized polypyrrole

We describe the selective measurement of extracellular glutamate concentration in rodent brain using ceramic-based platinum microelectrode arrays (MEAs) coated with electropolymerized, over-oxidized polypyrrole (OPP) as a permselective barrier to interference from dopamine and ascorbate. OPP-coated MEAs displayed similar sensitivity (97 +/- 9 nA microM(-1) cm(-2)) and response time (ca. 1 s) to glutamate as previously described Nafion-coated MEAs but, unlike Nafion-coated MEAs, were unresponsive to 5 microM dopamine. Such OPP-coated MEAs afforded selective detection of evoked glutamate release in the dopamine-rich striatum of the mouse brain.