固态pH 探测电极的制备及其性能表征

我们采用熔融碳酸锂(LiCO3)氧化法制备了固态Ir／IrO2 pH电极，同时制备了改进型固态Ag／AgCl参比电极，并对它们的性能进行了表征。实验结果显示，在pH=0-14的溶液中，Ir／IrO2电极与参比电极电位差与pH值呈现良好的线性关系，直线斜率为-62．429mV／pH，截距为607．97mV，相关系数R2=0．993。温度对新型pH传感器响应信号的影响符合Nernst方程，易于进行温度校正。盐度对电信号强度的影响是线性的，在介质盐度已知，或向步测定介质盐度的前提下，可从响应电信号强度及盐度确定待测介质的pH值。     

全固态裸露式Ag／AgCl参比电极的研制及应用

该文报道了一种树脂接界全固态裸露式Ag／Agcl参比电极,勿需电镀氯化,制备工艺简单,性能稳定,是对电解型Ag／AgCl参比电极的一大改进。可代替饱和甘汞电极作为通用型参比电极,同时可减少汞对环境所造成的二次污染,在温度大于75℃时仍能保持良好性能,突破了甘汞电极的局限。     

基于空心微针阵列的连续监测葡萄糖传感器

研制了一种基于空心微针阵列并可微痛刺入皮下实时连续监测人体血糖浓度的葡萄糖传感器.微针阵列由等间距的三根微针组成,分别作为工作电极、辅助电极和参比电极,其中工作电极与辅助电极采用表面溅射了Ti/Pt的空心不锈钢微针来制作,采用戊二醛-牛血清白蛋白交联法将葡萄糖氧化酶固定并仅置于作为工作电极的针尖通孔处;参比电极采用Ag/AgCl实心微针制作.测试结果表明:葡萄糖浓度在0～21 mmol·L-1范围内传感器输出电流为线性,灵敏度为0.575 μA/(mmol·L-1),响应时间为16s,且具有很好的抗干扰性.     

化学修饰GOD传感器

利用电化学修饰GOD工作电极及Ag/AgCl参考电极组装成了检测葡萄糖的GOD传感器．在0．7V的极化电位下，孩传感器对葡萄糖的响应电流小于1μA时，此电流与葡萄糖浓度成正比．传感器线性范围2．0×10-5至1．3×10-3mol／L，响应时间10s，稳定工作寿命150次，测量变异系数为2.73％。     

基于集成参比电极的多参数水质监测微传感器阵列研制

研究了一种基于MEMS工艺制备的集成微电极型传感器,并用电化学修饰方法将Ag/AgCl参比电极集成在传感器上,用于水体中温度、电导率和氧化还原电位的测定.Pt温度传感器的电阻与温度的线性关系良好,满足温度测量精度的需求;比较法确定电导率传感器的电极常数为2.723,可以对一般水体的电导率进行测定;氧化还原电位传感器的标...     

银、L-半胱氨酸修饰电极同时测定多巴胺和抗坏血酸

采用电聚合的方法将银、L-半胱氨酸先后修饰到电极表面,制备了银、L-半胱氨酸修饰电极fPLC／Ag／GCE）。研究了多巴胺和抗坏血酸在该修饰电极上的电化学行为,构建的电极可实现对多巴胺和抗坏血酸的同时检测。实验表明：在扫速为120mV／s,pH=3．0的磷酸盐缓冲溶液（PBS）中,多巴胺产生一对氧化还原峰,其氧化峰和还原峰的电位分别为0．447V和0．409V;而抗坏血酸只产生一个明显的氧化峰,其峰电位为0．238V。多巴胺和抗坏血酸的AEpa=0．209V,不需要分离便可对两者进行同时检测。在最佳条件下,测定多巴胺和抗坏血酸的线性范围分别为1．00×10-6～2．50×10-4mol/L和7．50×10-6--1．00×10-3mol／L．检出限分别为5．0×10-7mol／L和2．5×10-6mol／L。该方法可用于多巴胺和抗坏血酸的同时测定。     

海底热液扩散流溶解硫化物的原位观测：电极的制备与性能标定

介绍了一种用于测定溶解硫化物浓度的新型离子选择电极(ISE)的制备方法和性能标定结果.以银丝为基材,用含超细银粉的导电聚合物作为中间层,在环氧树脂固化后通过化学反应形成Ag2S层.以新型Ag/Ag2S为工作电极,以Accu-ment公司的Ag/AgCl为参比电极,构成溶解硫离子/硫化氢传感器.性能标定结果显示,这种新型固态传感器的响应电信号与硫离子浓度的对数呈线性关系,线性范围为10-2～10-7(mol/L)的硫离子.所测电压与硫离子浓度的对数之间斜率为-27.7,与理论计算得到的能斯特斜率dE/dloga;(-29.6 mV)接近.它在响应速度、探测灵敏度和工作稳定性等方面均明显优于传统的ISE型传感器.     

电化学CO气体传感器及其敏感特性

介绍了电化学CO气体传感器的结构,辅助电极、Ag/AgCl参比电极的制作以及工作电极的修饰和制作方法,研究了该传感器对CO气体的敏感特性。实验结果显示:活化处理后的Pt溶胶修饰的Pt丝微电极对CO气体有良好的敏感特性,CO氧化峰尖锐、峰形良好,在低浓度范围内,其峰电流与CO的浓度成良好的线性关系,表明此传感器适于定量检测CO的浓度。     

水溶液中（P—Cl）TPPMnCl修饰的炭糊电极上O2的活化

前文已报道了(P-Cl)TPPFeCl 修饰的炭糊电极上分子氧的电催化还原.本文将主要报道锰卟啉修饰的炭糊电极的性能及其对分子氧的电催化活化的机理。一、实验一、仪器及试剂79—1型伏安分析仪(河南电分析仪器厂);3086型 X—Y 函数记录仪(四川仪表四厂);三电极系统:修饰电极为工作电极;Ag/AgCl 为参比电极;铂丝为电极。本实验所用试剂均为 AR 级;各种水溶液皆用蒸馏水配制。二、修饰电极的制备将锰卟啉的二氯甲烷溶液移到炭糊电极表面或将炭糊电极浸入到锰卟啉的二氯甲烷溶液中吸附30分钟,都可以制得修饰电极。三、实验步骤1.在中性或酸性溶液中,通 N_230分钟除去 O_2,分别在+0.5V～-0.5V,+1.2V     

基于微纳泡沫金属材料的D-半乳糖传感器研究

研究了一种基于微纳泡沫镍材料的D-半乳糖定量传感器,采用泡沫镍材料作为工作电极,Pt作对电极,Ag/AgCl（饱和KCl溶液）电极作为参比电极构建三电极检测体系,采用循环伏安法（CV）和电流-时间曲线法（i-t）检测具有浓度梯度的D-半乳糖溶液。CV扫描结果表明了D-半乳糖在泡沫镍材料上发生氧化-还原反应,i-t检测结果表明在线性范围0.25 mmol/L~5.00 mmol/L内该传感器检测D-半乳糖的灵敏度为6.73×10-2 mA/（cm2·（mmol/L））,检测限为17.7μmol/L（S/N=3）。结果证明所构建的检测方法不但可以实现D-半乳糖的定量分析,并且具有较好的灵敏度和较低的检测限。对比实验结果表明该传感器具有响应速度快、成本低廉等优势,有望在糖类物质快速定量检测领域得到应用。     

Acetylthiocholine/acetylcholine and thiocholine/choline electrochemical biosensors/sensors based on an organically modified sol–gel glass enzyme reactor and graphite paste electrode

Electrochemical sensors for acetylthiocholine and acetylcholine are described. The non-mediated electrochemistry of acetylthiocholine and thiocholine is studied on the surface of graphite paste electrode and results show that acetylthiocholine is directly oxidized/reduced at >0.32 V vs. Ag/AgCl in both acidic and basic medium. In basic medium, both cathodic and anodic peak currents are less as compared to that of the same amount in acidic medium, which shows that the kinetics of non-enzymatic hydrolysis of acetylcholine into electroactive thiocholine is faster in acidic medium and slower in basic medium. Thiocholine is directly oxidized/reduced at >0.35 V vs. Ag/AgCl with relatively larger anodic current compared to cathodic peak current similar to that of acetylcholine results recorded in acidic medium (pH 6.0). The electrochemical sensor/biosensors for acetylthiocholine/acetylcholine and thiocholine/choline are developed using two enzyme reactors: (1) acetylcholinesterase (AChE) encapsulated organically modified sol–gel glass, and (2) choline oxidase (ChO) immobilized within mediators (tetracyanoquinodimethane (TCNQ), tetrathiafulvalene (TTF), and dimethyl ferrocene (dmFc))-modified graphite paste electrodes. The AChE-immobilized into organically modified sol–gel glass behaves as the reactor for enzymatic hydrolysis of acetylthiocholine/acetylcholine into thiocholine/choline, whereas mediator- and ChO-modified paste electrodes are used for the detection of thiocholine/choline through mediated mechanism. The electrochemistry of AChE-generated thiocholine is studied at the mediator-modified electrodes in the presence and absence of ChO. It is observed that thiocholine undergoes both mediated and non-mediated oxidation in the absence of ChO as well as oxidation through enzyme-catalyzed mediated reactions. The results based on cyclic voltammetry on the oxidation of thiocholine at the surface of mediator-modified electrodes in the presence and absence of ChO are reported. In the presence of the ChO large anodic current is observed near the mediator's redox potentials as compared to the anodic current in the absence of enzyme, which shows mediated bioelectrochemistry of thiocholine. The typical response curves for the detection of thiocholine/choline using mediators and ChO-modified electrodes below 0.24 V vs. Ag/AgCl in 0.1 M Tris–HCl buffer pH 8.0 are reported. Comparative analytical performance on the mediated electrochemical responses of the biosensors is discussed.     

金属／YSZ电极对氧传感器性能的影响

借助交流阻抗谱测试技术和扫描电镜,对Pt,Au,Ag,Ag—Pt,Ag—Pd电极浆料所制金属／YSZ电极的界面电阻、激活能进行了研究,并计算了由其构成的氧传感器达到90％响应量所需时间。研究表明：400-600℃时,02在Ag／YSZ电极上反应速率最快,激活能最低,为91kJ·mol^-1;Pt／YSZ电极激活能最高,为183kJ·mol^-1,电极反应速率控制步骤为吸附氧原子在电极表面的扩散过程;Ag—Pt,Ag—Pd／YSZ电极激活能均较Ag／vsz电极高,Pd含量增大时,Ag—Pd／YSZ电极激活能亦增大;400-450℃时,Ag／YSZ氧传感器响应时间最短,450-600℃时,Ag-1％Pd／YSZ氧传感器响应最快。     

Dynamic feedback regulation of the potential of a microfabricated liquid-junction Ag/AgCl reference electrode

A negative feedback mechanism to correct the deviation in the potential of a microfabricated Ag/AgCl electrode was developed using a nonstandard three-electrode system consisting of only thin-film Ag/AgCl electrodes. The reference electrode in the nonstandard three-electrode system was surrounded by a Ag/AgCl auxiliary electrode and provided a standard potential for other electrodes used for detection. With a constant potential applied to the Ag/AgCl working electrode with respect to the reference electrode, the shift of the reference electrode potential caused by a solution having different Cl⁻ concentration flowing in a neighboring flow channel polarized the working electrode slightly. Because of the nonpolarizable nature of Ag/AgCl, the slight shift of the potential of the working electrode caused a rapid current increase, resulting in the recovery of Cl⁻ concentration around the reference electrode. The effect of the feedback function was confirmed by comparing the results with those obtained from cases without the feedback function and from the potentiometric detection of Cl⁻ ions in a solution flowing in a flow channel.     

A VOLTAMMETRIC FLAVIN MICROELECTRODE FOR USE IN BIOFILMS

Biofilms used in bioelectrochemical systems are expected to transfer electrons using electron transfer mediators. One mediator type, flavins, which includes flavin mononucleotide, riboflavin, and flavin adenine dinucleotide, has been found to be endogenously produced by Shewanella oneidensis MR-1. However, the presence and concentration of flavins inside a S. oneidensis MR-1 biofilm have never been reported. The goal of this study was to develop a flavin microelectrode capable of measuring flavins inside a living biofilm and apply it to a biofilm which produces flavins. Because flavins are electrochemically active molecules, the flavin microelectrode was based on detection via square-wave voltammetry. The microelectrode consisted of a carbon working electrode with a 10-30 μm tip diameter, a built-in platinum counter electrode, and a Ag/AgCl reference electrode, all enclosed in a glass outer case. The microelectrode was calibrated between 0.1 μM and 10 μM flavins and showed a linear correlation between flavin concentration and peak currents located at -424 mV(Ag/AgCl) on a square-wave voltammogram. We also developed a model to explain the electrochemical mechanism of flavin detection, and to determine the effective surface area of the microelectrode, the standard reduction potential, and the transfer coefficient. We found that the effective surface area of the microelectrode was close to 100 times the projected surface area. The model predicted a standard reduction potential for RF/RFH2 of -419 mV(Ag/AgCl) at 20 °C and a transfer coefficient of 0.45. Lastly, we measured flavin concentration inside a S. oneidensis MR-1 biofilm grown on a glass surface using oxygen as the electron acceptor. The flavin concentration reached 0.7 μM, increasing near the bottom of the biofilm, where no oxygen was present. This shows the possibility that flavins are produced in the anaerobic zone to act as intermediate electron acceptors in the deeper parts of the biofilm, where there is no oxygen.     

基于固态Ag/AgCl参比电极的氧化钨pH电化学传感器的研究

通过浸涂法在钨金属丝上涂敷氧化钨氢离子敏感膜,制备了氧化钨H 选择性电极,采用尿素改性聚乙烯醇作为参比电极的固态薄膜材料并进行KCl掺杂,经Nafion膜进行修饰后制备了固态参比电极.利用自制的氧化钨pH电极与固态参比电极制成pH电化学传感器,该传感器具有良好的响应电位E-pH线性函数关系,响应范围为pH2～pH11.响应灵敏度与氧化钨的热处理温度有关,200℃热处理后的响应灵敏度为52.81 mV/pH, 响应时间与氧化钨敏感膜、测试溶液pH值以及溶液温度有关.在pH2→pH11→pH2循环测试过程中,传感器的滞后效应较小.该传感器有良好的选择性,响应行为不受Na 、F-等常见离子的影响,但是受到氧化还原性的NO-3、I-等离子的干扰.传感器内阻很低为22.8 kΩ,远小于玻璃pH计的内阻(1×109 Ω).该传感器在各种饮料中具有较高测量精度,与玻璃pH计的测量值进行对比,两者的差值在(-0.06 pH, 0.15 pH)范围内.在10-5M→10-1M柠檬酸溶液中,传感器的响应电位与溶液浓度存在良好的线性关系,响应时间小于1 min.     

Thin-Film Piezoelectric Unimorph Actuator-Based Deformable Mirror With a Transferred Silicon Membrane

This paper describes a proof-of-concept deformable mirror (DM) technology, with a continuous single-crystal silicon membrane reflecting surface, based on$ PbZr _0.52 Ti_0.48 O _3$(PZT) unimorph membrane microactuators. A potential application for a terrestrial planet finder adaptive er is also discussed. The DM comprises a continuous, large-aperture, silicon membrane “transferred” onto a 20$,times,$20 piezoelectric unimorph actuator array. The actuator array was prepared on an electroded silicon substrate using chemical-solution-deposited 2-$mu m$-thick PZT films working in a$d _31$mode. The substrate was subsequently bulk-micromachined to create membrane structures with residual silicon acting as the passive layer in the actuator structure. A mathematical model simulated the membrane microactuator performance and aided in the optimization of membrane thicknesses and electrode geometries. Excellent agreement was obtained between the model and the experimental results. The resulting piezoelectric unimorph actuators with patterned PZT films produced large strokes at low voltages. A PZT unimorph actuator, 2.5 mm in diameter with optimized PZT/silicon thickness and design showed a deflection of 5.7$~mu m$at 20 V. A DM structure with a 20-$mu m$-thick silicon membrane mirror (50 mm$times,$50 mm area) supported by 400 PZT unimorph actuators was successfully fabricated and optically characterized. The measured maximum mirror deflection at 30 V was approximately 1$~mu m$. An assembled DM showed an operating frequency bandwidth of 30 kHz and an influence function of approximately 30%. 1738     

Direct electrochemistry and electrocatalysis of myoglobin immobilized in zirconium phosphate nanosheets film

Myoglobin (Mb) is incorporated on a novel matrix—zirconium phosphate nanosheets (ZrPNS) and immobilized at a glassy carbon electrode surface. UV–vis spectra and electrochemical measurements show that the matrix is well biocompatible and can retain the bioactivity of immobilized Mb. The direct electron transfer between Mb and electrode exhibits a couple of well-defined redox peaks. The cathodic and anodic peaks are located at −0.340 and −0.280 V vs. Ag/AgCl, respectively. The ZrPNS can improve the electron transfer between Mb and electrode with an electron transfer constant of 5.6 s⁻¹. Meanwhile, the catalytic ability of the protein toward the reduction of H₂O₂, O₂, NaNO₂, trichloroacetic acid (TCA) is also studied and a third-generation biosensor is subsequently fabricated. The linear range of biosensor to H₂O₂ is from 8 × 10⁻⁷ to 1.28 × 10⁻⁵ M with the limit detection of 1.4 × 10⁻⁷ M. The small apparent Michaelis–Menten constant (34 μM) suggests that Mb/ZrPNS film performs good affinity with H₂O₂. The biosensor also exhibits acceptable stability and reproducibility. This work paves a way to develop other biologic active materials in this kind of nanosheets for constructing novel biosensors.     

PVP/Pd/IrO2电化学修饰电极的研究及其应用

本文研制了一种新型的 PVP/Pd/IrO_2电化学修饰电极。在 Pt 电极表面先后修饰 PVP(Poly VinylPyridine)及 Pd/IrO_2,该修饰电极对 HSO_3~-有良好的催化氧化作用;同时,在恒电位+0.6V 条件下,以该修饰电极与 Ag/AgCl 电极,Pt 对电极组成的气体传感器,对 SO_2也有良好的响应,预计在环境监测及环境保护等领域有应用前景。