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。     

用苯噻草胺吸附伏安法测定植物DNA

提出了用苯噻草胺作为电化学指示剂,在悬汞电极上以吸附伏安法测定DNA的新方法.在pH4.4的醋酸盐缓冲溶液中,BTMPA与植物DNA形成的复合物在悬汞电极上于-1.53 V左右产生一吸附伏安峰,利用此峰测定稗草DNA的线性范围为0.75μg/L～7.5×103μg/L,检测限低至0.75μg/L;水稻DNA线性范围为7.5 mg/L～37.5 mg/L,检测限为0.30 mg/L;玉米DNA线性范围为5.0 mg/L～50.0 mg/L,检测限为0.37 mg/L.     

基于Pt/石墨烯纳米复合材料的甲醛电化学传感器

采用电沉积的方法制备了Pt/石墨烯纳米复合材料,考察了该复合材料的电化学性能,用于甲醛的检测,表现出良好的检测性能.实验结果表明:在0. 1 mol/L的H2 SO4 溶液中,Pt/石墨烯纳米复合材料修饰电极可以实现在2 ×10 -6 ~2 ×10-3 mol/L浓度范围内甲醛浓度的检测,最低检测限为1 ×10-6 mol/L,并且具有高的灵敏度和良好的重现性.     

一种基于泡沫铜材料的无酶果糖传感器研究

本文尝试了一种基于泡沫铜材料的无酶果糖传感器。以泡沫铜材料作为工作电极,Pt片作为对电极,在0.1 mol/L的NaOH溶液中以循环伏安法( CV)和电流-时间曲线法( i-t)探索了一种无酶果糖的定量检测方法。 CV扫描结果证明果糖在泡沫铜电极表面易被氧化。 i-t检测结果表明在线性范围0.18 mol/L~3.47 mol/L内泡沫铜电极检测果糖的灵敏度3.1930 mA/( cm2·mmol/L),其检测限为13.8μmol/L。对比实验表明,泡沫铜电极对果糖具有较好的选择性。该传感器具有响应速度快、成本低等优势,有望于糖类检测中得到应用。     

纳米ZnO／TiO2复合膜传感器的制备及其应用于地表水中化学需氧量测定的研究

该文利用光催化氧化技术建立了一种测定地表水等低污染水体COD值的新方法.纳米ZnO/TiO2复合膜与单纯的纳米TiO2膜相比,提高了系统的电荷分离效率,扩展了其光谱响应范围,从而表现出更好的光催化效率.纳米ZnO/TiO2复合膜-Mn(Ⅶ)共存体系光催化降解水体中的有机物,COD值在0.3～10.0mg/L浓度范围内与信号成线性关系,检测限为0.1 mg/L.将该方法用于实际水样的检测,测定结果与COD标准分析法有较好的一致性.     

纳米Pt修饰Pt电极检测芥子气的研究

采用纳米Pt修饰Pt电极、在0.8mol/L H2SO4-50%CH3CN电解质体系中,同时检测出芥子气分子中的特征基团-S-和-Cl,使HD的检测结果具有特征性。采用方波伏安法,能够更有效分辨芥子气分子中-Cl的电化学信号,芥子气的检测限为0.1μg/mL。在研究检测芥子气的机理中发现,芥子气分子中的-S-基团在电化学氧化过程中,在工作电极上失去的电子,经外电路传递到对电极,电解质溶液中的溶解氧在对电极表面发生O2+4H++4e→2H2O的电化学还原反应,使得工作电极的输出电子被消耗,电化学闭合回路的电流得以有效流通,电解质溶液中的溶解氧对-S-的氧化过程有至关重要的作用,外在表现为芥子气的检测灵敏度有显著提高。     

以萘酚绿B为介体的葡萄糖生物传感器

该文以聚乙烯醇缩丁醛为固定葡萄糖氧化酶(GOD)的载体,将GOD附在铂丝电极上制得葡萄糖酶电极.文中讨论了溶解性媒介体萘酚绿B的浓度、溶液的pH值和温度对该电极电流响应的影响.这一介体型葡萄糖传感器在优化的实验条件下,对葡萄糖表现出良好的响应特性,如响应快、重现性和稳定性好.传感器线性范围为8.0×10-4mol/L～3.6×10-2mol/L,相关系数为0.9933,检测限为5.0×10-4mol/L.     

TiO2光催化传感器的制备及其在化学需氧量测定中的应用研究

该文采用溶胶凝胶法制备了TiO2薄膜电极,并首次提出了一种基于TiO2膜电极/溶液界面电荷传递的化学需氧量(COD)的测定方法.以葡萄糖为响应底物,考察了TiO2薄膜电极的光催化行为,结果发现该传感器的光电流信号与COD值在0.5～235 mg/L范围内有很好的线性响应,相关系数为0.9998.该方法具有测试速度快,不需有毒、昂贵试剂,以及便于实现自动化等优点,有着广阔的应用前景.     

苯胺红T与辣根过氧化氢酶共固定无试剂过氧化氢传感器的研制

将辣根过氧化氢酶(HRP)与氧化还原型染料苯胺红T(ST)用戊二醛交联共固定在玻碳电极的表面,制得了无试剂过氧化氢传感器.该传感器在水溶液中显示了很好的电化学活性.苯胺红的表现覆盖度为9.22×10-11mol/cm2,苯胺红与玻碳电极之间的异相电子转移速率常数为0.066 s-1,研究了响应时间、检测限、检测电位、溶液pH和测定温度等因素对传感器性能的影响.在优化条件下,该传感器对过氧化氢的最低检测限为1.0×l0-7mol/L.多巴胺、抗坏血酸和尿酸等不干扰过氧化氢的测定.而且,该酶电极显示了较好的稳定性.     

基于NaOH刻蚀玻碳电极的电化学传感器在检测膀胱癌DNA中的应用

制备了一种基于活化的玻碳电极的新型电化学DNA生物传感器,可用于膀胱癌DNA的检测.通过循环伏安法(CV)实现玻碳电极在NaOH溶液中的刻蚀,使电极表面负载大量官能团,为DNA提供连接位点,由Laviron方程计算得到玻碳电极表面的羧基浓度为 1.022×10-6 mol/cm2.亚甲基蓝(MB)作为电化学检测的杂交指示剂.采用原子力显微镜(AFM)对刻蚀后的电极进行了形貌表征.在最优杂交条件下,通过差分脉冲法(DPV)计算出最佳检测限为5.677×10-13 mol/L(n=5),适用目标 DNA浓度范围1×10-8 mol/L~1×10-12 mol/L.该传感器有望用于实际样品中膀胱癌DNA的快速检测.     

金属纯度智能检测装置的研究

对于金属元素来说,纯度的改变会影响金属特性。当对一些金属进行纯度检测或者判断它的杂质含量时,不准确的检测结果也会直接影响对这些金属的性能评价,因此研究了一种金属纯度智能检测装置。用电极电导法测量金属-有机溶剂二元溶液体系,在恒流的情况下测量不同金属在浸溶液状态下的电压情况,采用Visual Basic编程语言设计软件,通过串行通信方式对电压和实时温度数据进行采集,对比电压数据曲线从而判断金属的纯度。经过实验测试表明,根据电压曲线区分金属、分析金属纯度的方法是可行的,所提出的分辨金属及检测金属纯度的方法实现了金属纯度检测的智能化、可视化。     

NASICON-based solid-electrolyte cell as transducer for enzyme sensors

Enzyme sensors for glucose and uric acid have been developed based on a solid-electrolyte cell using NASICON (Na₃Zr₂Si₂PO₁₂). These potentiometric devices respond reversibly to glucose and uric acid over a concentration range of two orders of magnitude with sensitivities of −54 and −52 mV/decade, respectively. The sensors can be used for a batch-type as well as a flow-through-type measuring system. Primarily the sensors respond to the H₂O₂ that is produced by the enzymatic reactions. The role of the three-phase region, electrolyte solution, sensing electrode metal and NASICON has been investigated. The liquid electrolyte/sensing electrode metal interface is found to work as a potential-determining as well as a rate-determining interface for the enzyme sensor.     

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.     

基于聚吡咯纳米线的硝酸根离子传感器的研究

在碳酸钠和碳酸氢钠水溶液中,使用电化学非模板法制备得到聚吡咯(polypyrrole)纳米线修饰电极,然后在高氯酸锂溶液中浸泡24 h.在0.5 mol/L硫酸溶液中,采用固相微萃取电流法(EC-SPE)来检测水中的硝酸根离子,所用固相萃取氧化电位为0.85 V,时间300s,还原电位为-0.15 V,还原时间100s.考察了聚合电量、被测试液温度、酸度、共存离子对该修饰电极检测水样中的硝酸根离子浓度的影响.硝酸根离子的浓度与还原电流密度呈良好的线性关系,检测极限和灵敏度分别是2.43×10-5mol/L和65.99 mA/M cm2.     

一种新型的铬（Ⅲ）离子选择性电极的研制与应用

以水杨醛和硫代氨基脲合成的席夫碱水杨醛缩-硫代氨基脲为中性载体,将其与碳粉混合,以液体石蜡为粘合剂,制备了新型的铬（Ⅲ）离子选择性电极。在室温下,电极对Cr3＋的能斯特响应浓度范围为4.00×10-7～1.00×10-2mol/L,斜率为20.31mV/dec,检测下限为1.58×10-7mol/L。电极的响应时间小于20s,pH使用范围广（3.20～5.80）,稳定性好,使用寿命长。在选定的条件下,用固定干扰离子法（FIM）考察了10余种离子的干扰情况,结果显示,电极对Cr3＋具有较好的选择性。以该离子选择性电极为指示电极,饱和甘汞电极为参比电极,用直接电位法对废水中的Cr3＋进行测定,结果令人满意。     

Finite Volume model for diffusion- and activation-controlled pitting corrosion of stainless steel

Steel corrosion plays an adversary, but central role in different technological fields. Reasonable modeling of corrosion calls for a profound theoretical study of the underlying mechanisms. The present paper is concerned with mathematical modeling of (localized) pitting corrosion: We derive the mass conservation law of a dissolving body hosting a metal/solution interface which separates the solid metal electrode from the liquid electrolyte, and we complement the mass balance law by a thermally activated, potential-dependent electrochemical kinetics law for the dissolution reaction and by Fick’s law for ionic transport in the electrolyte solution. As long as the electrolyte solution adjacent to the electrode boundary does not reach its saturation level, the Arrhenius-type dissolution kinetics law governs the dissolution rate, and Fick’s law governs solely the concentration distribution in the electrolyte solution (activation-controlled corrosion mechanism). However, once the saturation level is reached at the electrode boundary, the pit depth evolution is governed by the diffusion of ions from the electrode boundary into the electrolyte-filled pit (diffusion-controlled corrosion mechanism). Corresponding mathematical solutions (time-dependent fields of concentrations) are obtained by means of the Finite Volume Method. For experimentally supported model input values (concerning dissolution activity, corrosion potential, transfer coefficient, metal charge number, ionic saturation concentration, and solid metal concentration), the influence of the overpotential on the corrosion characteristics (pit depth and shape evolution, current density, ionic concentrations in electrolyte) is shown by means of 1D and 2D simulations.     

基于头孢克肟的荧光熄灭效应用于微量铬(VI)的灵敏检测

利用Cr(VI)对头孢克肟的荧光淬灭效应,建立了一种微量金属铬的荧光探针分析方法。以甲醇-盐酸(1.0×10-3mol/L)溶液(1∶1,V/V)为介质,最大激发与发射波长分别为397 nm和438 nm,头孢克肟荧光强度与Cr(VI)浓度对数呈良好的线性关系,其线性范围为1.0×10-6~2.0×10-3mol/L,线性方程可拟合为F=-25.09 lgc-36.61(r=0.995 6),检测限为5.8×10-7 mol/L。常见的共存离子不干扰测定,此方法可用于环境水样中Cr(VI)含量的测定。     

同心圆柱环型电容式肥液浓度传感器设计与试验

设计了一种同心圆柱环型电容式肥液浓度传感器,主要由稳压器、10MHz有源晶振、施密特触发器、电容传感器和真有效值检测器组成,检测结果以直流电压形式输出.在8×10 -1~1×10 -3mol/L浓度范围内,配置一系列待测肥液对传感器进行了试验:1)标定试验结果表明传感器输出电压与浓度对数呈线性负相关,决定系数R2>0.987;2)温度变异性试验结果表明传感器输出电压与肥液温度呈线性正相关,其决定系数R2=0.98417;3)稳定性试验结果表明同一浓度下连续测量10 h内测量最大差值为0.0003 mol/L,传感器稳定性良好;4)验证试验结果表明最大检测误差为9.8%.满足在线检测的实际应用要求.     

Detection of heavy metal ions in aqueous solution by P(MBTVBC-co-VIM)-coated QCM sensor

A novel copolymer P(MBTVBC-co-VIM) was designed and successfully synthesized for the fabrication of copolymer-coated QCM sensors to detect the heavy metal ions in aqueous solution. The copolymer P(MBTVBC-co-VIM) contains many nitrogen (N) and sulfur (S) atoms in the side groups as electron donors, which can easily form complexes with heavy metal ions. The strong interaction between the S atom and Au electrode of quartz crystal further assures the stability of copolymer thin films on the quartz crystal surface in aqueous media. The QCM results indicated that the P(MBTVBC-co-VIM)-coated sensor exhibited high sensitivity, stability and selectivity for the detection of Cu²⁺ in aqueous solution. The lowest detection limit can reach 10 ppm Cu²⁺ in aqueous solution, which resulted in the frequency shift of 3.0 Hz (ΔF₃/3). The P(MBTVBC-co-VIM)-coated QCM sensors had porous surface morphologies as revealed by AFM investigation. Such porous structures enhanced the surface areas of the copolymer thin films, which increased the contacting probability of N and S atoms with heavy metal ions in solution and improved the detection sensitivity of the copolymer-coated QCM sensors.     

基于Hg~(2+)诱导DNA双链形成的汞离子检测试纸条研制

Hg2+能特异性地与2个胸腺嘧啶碱基(T)共价结合,介导T-T错配形成稳定的T-Hg2+-T结构。基于DNA修饰的纳米金探针研制了一种可检测水溶液中Hg2+浓度的层析试纸条。试纸条包含1条控制线和2条测试线,检测结果在5 min内可见,裸眼可见检测灵敏度为100 nmol/L。金标条阅读仪分析结果在10 nmol/L~10μmol/L范围内具有良好的线性关系,且对常见二价重金属离子Cu2+,Ni2+,Mg2+,Zn2+,Pb2+具有很好的选择性。该试纸条灵敏特异、快捷简单、操作方便、成本低廉,在环境监测和食品安全的现场快速检测中具有很好的应用前景。