基于还原氧化石墨烯修饰电极和智能手机的小型电化学分析仪

目的:设计一款基于智能手机的小型电化学分析仪,以实现对不同浓度的葡萄糖溶液的定量检测.方法:通过还原氧化石墨烯对工作电极表面进行功能化,制备了高灵敏度的葡萄糖传感器.采用LMP91000传感芯片设计而成的恒电位仪模块为传感器提供特定的激励信号并将测得的实验结果无线传输到智能手机上.采用智能手机进行数据处理和浓度计算,并...     

基于DNA-AuNPs信号放大的肠出血性大肠埃希菌快速检测电化学生物传感器

快速检测肠出血性大肠埃希菌(EHEC)有利于疾病的早期诊断,为医生合理使用药物提供指导。本实验基于DNA修饰的金纳米粒子(DNA-AuNPs)与亚甲蓝(MB)结合进行信号放大构建了一种灵敏的电化学生物传感器。采用透射电镜(TEM)和紫外可见吸收光谱(UV-Vis)对该生物传感器的修饰进行表征,利用交流阻抗法(EIS)、循环伏安法(CV)和差分脉冲伏安法(DPV)进行电化学性能检测。该方法的检测范围是100pM到50nM,检测限为75pM(S/N=3)。与传统细菌分离培养方法相比,该方法具有快速、灵敏等优点,对EHEC的早期诊断有着巨大潜力。     

基于碳纳米管-纳米金甲醛气体电化学传感器的研究

多孔气体扩散电极的制备是甲醛电化学传感器开发的关键所在.通过柠檬酸三钠还原法合成了纳米金-碳纳米管催化剂,制备了甲醛电化学传感器多孔气体扩散电极,并对催化剂和多孔扩散电极进行SEM、EDS、XRD表征.在甲醛气体浓度为0.24 mg/m3和0.63 mg/m3时对组装的传感器进行了响应性能测试.甲醛浓度在0.10～0.84 mg/m3时,传感器的线性方程为:y=10.291x+4.4161(R2=0.9960),响应时间大约80 s.     

基于石墨烯及室温离子液体的弓形虫IgM抗体免疫传感器的研制

在玻碳电极表面修饰石墨烯-室温离子液体(GP-BMIMPF6),利用金磁纳米粒子(Au-Fe3O4)对弓形虫抗原(Tg-Ag)的高效固定,构建了用于弓形虫IgM抗体(Tg-IgM)检测的新型电化学免疫传感器.采用循环伏安法(CV)、交流阻抗法(EIS)和差分脉冲伏安法(DPV)进行电化学检测.在优化条件下,响应电流与Tg-IgM的浓度分别在5×10-4～3.13×10-2 AU/mL和3.13×10-2～32 AU/mL范围内呈线性相关,检测限为2.8×10-4 AU/mL.该传感器经外部磁场再生25次后,相对标准偏差(RSD)仅为未再生时的6.8％;血液中可能存在的干扰物对该传感器造成的检测最大偏差小于4.61％;该传感放置24天后进行检测,电流仅下降为最初的91.4％,具有良好的重复性和稳定性,可以应用于血清标本中Tg-IgM的检测.     

SO_2电化学传感器温度特性及温度补偿研究

为削弱电化学传感器温度漂移对检测气体之干扰,研究了SO2电化学传感器的温度特性,提出了根据传感器所输出零点电流与反应电流的温度特性获取其最佳定标温度,并对基于曲线拟合的温度补偿算法做出扣除零点电流的改进,通过设计的基于TMS320F28335DSP的SO2电化学传感器检测系统做出了相应验证。实验结果表明,宽动态温度范围内,基于最佳定标温度27℃下的温度补偿结果平均误差为2.39%,比基于实验室常温20℃定标减小了24.84%,提高了检测精准度,同时也给其他电化学传感器温度特性研究提供了借鉴方案。     

基于电化学传感器的SF6分解气体检测技术研究

SF_6气体绝缘类电力设备具有体积小、结构紧凑、绝缘性能稳定、运行可靠等优点,被广泛应用于特高压和超高压电力系统中。当电力设备内部发生绝缘故障时,绝缘气体SF_6由于局部放电及局部过热发生分解反应,最终生成数种稳定SF_6分解气体,通过对这些分解气体组分进行定量检测和分析,可反演出设备内的故障或安全隐患。通过搭建电化学传感器响应特性的测试平台,在气体检测罐中模拟SF_6分解气体并进行检测,得到了CO、SO_2和H_2S气体电化学传感器的响应特性。实验结果显示出CO传感器有负的温度特性,SO_2和H_2S电化学传感器具有正的温度特性,并采用二次曲线拟合确定了传感器的温度补偿曲线;同时还发现CO、SO_2和H_2S气体传感器均具有良好的线性特性,但SO_2传感器会对H_2S气体做出响应,通过采用交叉干扰计算,建立传感器信号矩阵算法保证了测量结果的准确度。最后,通过运用多组分混合气体验证了传感器信号矩阵算法具有很高的可靠性和准确度。     

基于单片机的H2S气体检测仪的设计

本文介绍了利用H2S电化学传感器对H2S气体浓度进行精确检测的单片机硬件电路、工作原理及软件实现方法。所选用的H2S电化学传感器及信号电桥放大电路能满足在常温下对H2S气体高精度、宽范围检测的要求;在软件设计时,对数据的处理采用了线性插值算法。另外。该系统还采用了分级报警的方式。     

光寻址电位传感器特性研究

对影响EIS(电解质溶液—绝缘层—半导体)型光寻址电位传感器(Light Addressable Potentiometric Sensor,LAPS)的特性参数进行研究.通过CHI660D型电化学工作站检测不同厚度LAPS芯片输出的光电流信号,分析了硅基底厚度与LAPS芯片检测灵敏度和检测量程之间的关系;还讨论了偏压大小对输出信号稳定性的影响,并在较低偏置电压下测试不同浓度的pH缓冲溶液,获得了较好的线性关系,线性相关系数为0.9991.     

LabVIEW环境下多路气体检测系统的设计

为了实时监测环境中的CO和O2浓度,设计了一种基于LabVIEW的多路气体检测系统.该检测系统通过电化学传感器采集气体浓度信息,C8051F020完成信号的A/D转化和电化学传感器的温度补偿,并将多通道数据通过串口发送到上位机.上位机使用LabVIEW进行编程,从而实现数据的采集、处理、分析、显示、保存及自校准标定功能.该系统具有检测精度高、结构简单、检测方便、界面友好等特点.     

基于金纳米颗粒修饰丝网印刷电极的胰蛋白酶原-2电化学免疫传感器

胰蛋白酶原-2是一种与胰腺疾病相关的生物标志物,在急性胰腺炎和胰腺癌的诊断中发挥重要作用。电化学免疫传感器具有高灵敏性和高特异性的特点,利用其实现对胰蛋白酶原-2的快速、灵敏、简便的定量检测对于临床诊断及即时检验具有重大意义。在本研究中,以胰蛋白酶原-2抗体作为生物分子识别元件,以三电极体系作为信号转换元件,构建基于金纳米颗粒修饰丝网印刷电极的电化学免疫传感器,对胰蛋白酶原-2进行定量检测。在构建过程中,采用化学交联的方法,借助戊二醛的交联作用将金纳米颗粒修饰在丝网印刷电极上,通过金纳米颗粒对抗体的吸附作用可以实现响应信号的放大,从而有效提升灵敏度。通过电化学阻抗谱对传感器的构建过程进行表征,采用差分脉冲伏安法对传感器的检测性能进行评估,结果显示本研究所构建的传感器在胰蛋白酶原-2浓度为2.0-50.0 ng/mL范围内具有良好的线性关系,线性相关系数为0.9954,检测限达0.65 ng/mL。此外,研究还对传感器的准确性与可重复性进行了评估,传感器对在样本中的胰蛋白酶原-2回收率为103.3%-110.5%。结果表明本研究所构建的电化学免疫传感器可实现对胰蛋白酶原-2的定量检测,具有良好的临床应用前景。     

Determination of ganciclovir as an antiviral drug and its interaction with DNA at Fe3O4/carboxylated multi-walled carbon nanotubes modified glassy carbon electrode

The electrochemical oxidation of an antiviral drug, ganciclovir (GCV) at Fe₃O₄/carboxylated multi-walled carbon nanotubes modified glassy carbon electrode (Fe₃O₄/cMWCNTs/GCE) was studied by voltammetric techniques. The influence of the effective parameters on the electrochemical behavior of GCV was investigated. Under optimized conditions, the proposed sensor was applied for low level GCV determination. The relationship between peak current and the concentration of GCV was linear in the range of 80–53,000 nM with a detection limit of 20 nM through square wave voltammetry (SWV). The interaction of GCV with calf thymus DNA was also explored by voltammetric and spectrofluorometric methods. Based on the obtained data the mode of binding of GCV to DNA was intercalative binding. The decrease in the SWV peak current of GCV in the presence of DNA was used for the determination of DNA. The modified electrode exhibited a good sensitivity, stability and pleasant reproducibility, and it was applied for the determination of GCV in spiked serum and urine, with satisfactory results.     

SENSITIVE L-CYSTEINE AMPEROMETRIC SENSOR BASED ON A GLASSY CARBON ELECTRODE MODIFIED BY MnO2 NANOPARTICLES

A sensitive amperometric sensor for the determination of L-cysteine was fabricated by electrodeposition of modified MnO₂ nanoparticles on a glassy carbon electrode. The morphology of the nanoparticles was characterized by scanning electron microscopy. Cyclic voltammetry was applied to investigate the mechanism of film formation and the electrochemical properties of the MnO₂ nanoparticle-modified electrode. The results of electrochemical experiments showed that the modified electrode had a favorable catalytic ability for the electrochemical oxidation of L-cysteine. Under optimized conditions, the MnO₂ nanoparticle-modified electrode exhibited a linear dependence on the concentration of L-cysteine from 1.0 × 10^?6 to 6.4 × 10^?4 M, and a detection limit of 8.0 × 10^?7 M (signal/noise = 3). The modified electrode was highly resistant towards typical inorganic salts and some biomolecules. In addition, the sensor was applied for the determination of L-cysteine in human serum with high accuracy, demonstrating its potential for practical applications.     

Electrochemical determination of hydrogen peroxide on a gold nanoparticle–nitrogen-doped graphene glassy carbon electrode

A novel nonenzymatic sensor based on gold nanoparticle–nitrogen-doped graphene was synthesized by electrochemical sequential deposition on the surface of a glassy carbon electrode. Nitrogen-doped graphene was synthesized by a hydrothermal method using graphene oxide and carbamide as the raw materials mixed in specific proportions. The gold nanoparticles were used in the electrochemical sensor to provide unique electronic and electrochemical properties. Under the optimized conditions, hydrogen peroxide was determined by differential pulse voltammetry with a linear relationship for concentrations from 1.0?×?10^?7 to 1.0?×?10^?5?mol?L^?1. The detection limit was 4.9?×?10^?8?mol?·?L^?1 (according to the 3σ rule) and the recoveries were 95.0–98.0%. This sensor is simple, reproducible, and demonstrates that nitrogen-doped graphene oxide has potential applications for electrochemical sensors.     

YSZ粉末对多孔铂电极活性的影响

多孔铂电极的活性对氧传感器的使用性能起着决定作用,通过电化学循环伏安测试(CV)和扫描电镜分析,研究了YSZ(氧化钇稳定的氧化锆)粉末对铂浆法制得的多孔铂电极活性的影响,其中,以循环伏安测试中的电流密度来表征多孔铂电极的活性.结果表明:随着铂浆中YSZ粉末的含量升高,所制得的多孔铂电极孔隙率和电化学反应活性明显升高,这可能是由于YSZ粉末的加入提高了多孔铂电极O2(g),Pt/YSZ体系的三相界面面积造成的.     

A Chitosan-Graphene Electrochemical Sensor for the Determination of Copper(II)

Graphite oxide was prepared by oxidizing graphite powder, reduced to graphene using hydrazine hydrate, and the grapheme was mixed with chitosan to form a composite that was used to modify a glassy carbon electrode for the determination of copper(II). The electrochemical behavior of the modified electrode was studied by cyclic and square wave voltammetries. The morphology and structure of the composite were characterized by infrared spectroscopy, transmission electron microscopy, and scanning electron microscopy. In addition, the proportion of composite material, pH, and adsorption time was optimized. Under the optimized experimental conditions, the sensor showed a linear dynamic range from 1.0 × 10^?9 to 1.5 × 10^?8 mol · L^?1 for copper(II) with a limit of detection of 4.3 × 10^?10 mol · L^?1 at a signal-to-noise ratio of three. The sensor displayed excellent electrochemical response and high sensitivity.     

工业电导信号测量仪的研制

提出了一种基于新的激励模式的电导信号测量仪.该装置采用双极性脉冲电压源作为激励源,与交流激励的电导测试系统相比,削弱了介质电极化现象,简化了电路设计,并提高了数据的采集速度和精度.同时还专门设计了具有防腐、避免电化学反应及带有温度补偿的专用电导测量探头.经测试,该系统测量准确、抗干扰能力强,满足了工业流程中溶液电导特性的实时测量要求.     

Nano composite system based on fullerene-functionalized carbon nanotubes for simultaneous determination of levodopa and acetaminophen

In this paper we report an electrochemical sensor based on fullerene (C₆₀)-functionalized carbon nanotubes composite for the sensitive determination of the levodopa (LD) and acetaminophen (AC). A modified electrode by fullerene-functionalized carbon nanotubes (CNTs) composite has been fabricated and its electrochemical behavior was investigated by cyclic voltammetry, chronoamperometry and differential pulse voltammograms. The modified electrode shows electrocatalytic activity toward LD oxidation in phosphate buffer solution (pH 7.0) with a reduction of the overpotential of about 270 mV and an increase in peak current. These conditions are sufficient to allow determination of LD and AC in the samples at fullerene-functionalized carbon nanotubes composite. The differential pulse voltammetry data showed that the obtained anodic peak currents were linearly dependent on the LD concentrations in the range of 0.5–2000 μM, with the detection limit of 0.035 μM. The prepared electrode was successfully applied for the determination of LD and AC in real samples.     

Adsorption effect of a cationic surfactant at carbon paste electrode as a sensitive sensor for study and detection of folic acid

The present study is the first report on the effect of cetyltrimethylammonium bromide (CTAB) on the electrochemical behavior of folic acid (FA) at the surface of carbon paste electrode (CPE) in real samples. The studies were performed by cyclic voltammetry (CV), chronocoulometry and differential pulse voltammetry (DPV). CTAB, with a hydrophobic C–H chain, could absorb at the CPE surface by hydrophobic interaction and then changed the electrode/solution interface, and eventually affects the electrochemical response of FA, confirming from the remarkable oxidation peak current enhancement. For investigation of the electrode properties, CV technique was used at the various scan rates. Electrochemical parameters including diffusion coefficient (D), electron transfer coefficient (α) and ionic exchanging current density (j_o) were determined for the FA at the surface of the electrode. Under optimized conditions, the proposed method showed acceptable analytical performances for FA in terms of linearity (over the concentration range from 0.01 to 1.5 and 1.5 to 10.0 μM), detection limit (2.89 nM), repeatability (1.37%) and stability (13% reduction in peak current after 60 days). After studying on the effect of probable interferences it was found that the method was free of the interferences. Finally, the proposed method was successfully applied for the determination of FA in real samples.     

油气润滑ECT传感器的轴向屏蔽电极及其影响*

建立UMIST型（带轴向接地屏蔽电极）和METC型（带轴向驱动屏蔽电极）油气润滑ECT传感器的三维物理模型,根据三维物理模型推导电容值和灵敏度数学表达式,并分析轴向屏蔽电极对传感器的敏感性和灵敏度均匀性的影响;采用线性反投影算法（Linear Back Projection,LBP）进行图像重建,并比较重建图像与真实图像的相对误差和相关系数。结果表明：2种轴向屏蔽电极均可消除边缘电容并提高传感器的敏感性;带轴向接地屏蔽电极使得传感器的灵敏度更加均匀,而带轴向驱动屏蔽电极的传感器则相反。带轴向接地屏蔽电极的传感器更适用于油气润滑中环状流的识别,其重建图像与真实图像的相对误差降低了28.79%,相关系数提高了14.05%。     

水环境痕量重金属检测的电化学传感器的研究

重金属是一种危险的污染物,往往长期积累在生物体内不可降解,在极其微量的情况下也会对各种生态系统产生不同程度的危害.文中采用汞膜玻碳圆盘电极,研制了一种用于监测水环境痕量重金属浓度的电化学传感器,基于差分脉冲阳极溶出伏安法(differential pulse anode stripping voltammetry,DPASV),实现了锌、镉、铅和铜4种元素的同时测定.结果表明:该传感器用于检测锌、镉、铅和铜的检出限分别为2.0 μg/L、1.9 μg/L、0.8 μg/L和0.7 μg/L.与其他重金属检测方法相比,该电化学传感器的特点是可同时快速检测多种重金属元素,传感器体积小,价格低,操作简单,灵敏度高,易于实现现场自动检测分析.