基于一次性薄层色谱电极高选择电化学发光分析法测定Ni(II)的研究

基于一种新的电极制作方法, 研制了具有薄层色谱分离功能的一次性薄层色谱电极. 结合该电极的分离、保留分析物于电极表面一定空间区域的色谱分离能力与电极表面电化学发光信号的空间分辨能力, 实现了分析物的高效分离与原位高灵敏度电化学发光(ECL)检测, 建立了电化学发光分析方法与薄层色谱分离方法联用的新技术. 并以Ni^2＋离子为代表探讨了这一方法的可行性和分析特性. 在最佳的实验条件下, 该方法测定Ni^2＋离子的线性范围为5.0× 10^－9～5.0×10^－6 g/mL, 检出限为1.5×10^－9 g/mL, 相对标准偏差为2.8% (c＝1.0×10^－6 g/mL, n＝11).     

自组装单层界面β-环糊精非电活性客体的电化学测定

提出了用电化学技术测定非电活性物质的新方法.利用合成的β-CD对甲苯磺酸基衍生物(Ts-β-CD)获得新型β-CD单层.虽然β-CD的覆盖率只有10%左右,但该单层对二茂铁表现出有效的主客体响应.界面上二茂铁的包络符合Langmuir吸附响应.利用Langmuir吸附等温式,得到二茂铁与β-环糊精形成包络物的包络常数为4.2×10⁴ mol^-1· L,二茂铁在该单层上的最大表面覆盖度为8.6×10^-12 mol/cm².当二茂铁溶液中含有非电活性物质间甲苯甲酸(mTA)或十二烷基磺酸钠(SDS)时,mTA和SDS与包络在电极表面的二茂铁发生客体竞争反应而使二茂铁的氧化还原峰电流降低.利用该原理,分别测定了非电活性物质mTA和SDS,线性范围分别为0.8~2.7 μ mol/L和5~100 nmol/L.     

高效液相色谱-化学发光方法同时测定血清中的肾上腺素、去甲肾上腺素和多巴胺

本文基于肾上腺素、去甲肾上腺素和多巴胺对鲁米诺-铁氰化钾化学发光体系的增敏作用，建立了一种高效液相色谱分离-化学发光检测体系同时检测三种物质；研究了试剂浓度、酸碱条件、流动相成分等参数对分析结果的影响。在优化发光条件下，以邻苯二甲酸氢钾-甲醇溶液（92：8）为色谱流动相，用C₁₈柱分离检测肾上腺素、去甲肾上腺素和多巴胺样品，肾上腺素线性范围为1×10^-8~5×10^-6g/mL，检测限4.0×10^-9g/mL；去甲肾上腺素线性范围是 5.0×10^-9~1.0×10^-6g/mL，检测限1.0×10^-9g/mL；多巴胺线性范围为5.0×10^-9~1.0×10^-6g/mL，检测限8.0×10^-10g/mL。本方法快速、简便而准确，且已成功用于血清中三种物质的分析。     

辣根过氧化物酶修饰电极在离子液体[EMIM]BF4中的直接电化学

将壳聚糖(Chi)-辣根过氧化物酶(HRP)-多壁碳纳米管(MWCNTs)的复合物修饰在玻碳电极(GCE)表面, 制备了HRP修饰电极(Chi-HRP-MWCNTs/GCE), 并将其用于在亲水性离子液体1-乙基-3-甲基咪唑四氟硼酸([EMIM]BF4)中HRP的直接电化学研究. 紫外可见光谱和红外光谱表明, HRP在复合物内保持了其原始构象. 电化学研究表明, 该修饰电极在[EMIM]BF4中的循环伏安图上出现了一对峰形良好、几乎对称的氧化还原峰, 式量电位为－0.247 V (vs. Ag/AgCl), 说明包埋在Chi-MWCNTs中的HRP与电极之间发生了直接电子传递; HRP在电极表面直接电子转移的速率常数ks为3.12 s－1; 在65 ℃的[EMIM]BF4中HRP仍然保持其活性; HRP修饰电极对过氧化氢的还原具有电催化作用, 其表观米氏常数Km为5.6×10－5 mol•L－1, 催化电流与过氧化氢浓度在5.0×10－7～5.0×10－5 mol•L－1范围内呈线性关系, 检出限为2.0×10－7 mol•L－1. 该研究为非水相生物传感器的构制提供了一种新途径.     

血红蛋白/带正电的纳米金层层自组装膜修饰电极的制备及其电催化性能

利用自组装技术和静电吸附作用, 将带正电荷的纳米金(nano-Au^Å)和带负电荷的血红蛋白(Hb)层层自组装于L-半胱胺酸(L-cys)修饰的金电极表面, 从而制得用于检测过氧化氢(H2O2)的无电子媒介体的第三代电流型生物传感器({Hb/nano-Au^Å}5/L-cys/gold). 通过电子显微镜技术和微量电泳技术考察了不同粒径正电荷的纳米金的相关特征; 通过交流阻抗技术、原子力显微镜技术、循环伏安法和计时电流法考察了电极表面的电化学特性, 并对该传感器的作用机理及性能进行了详细的研究. 用计时电流法测得H2O2的线性范围为2.1×10^-8 ~ 1.2×10^-3 mol/L (r = 0.994), 检出限为1.1×10^-8 mol/L, 米氏常数(K_m^app)为0.10 mmol/L. 实验结果表明, 该方法与单层带正电的纳米金固载血红蛋白及带负电的纳米金层层自组装固载血红蛋白相比, 显著提高了血红蛋白的固定量, 并能保持血红蛋白的生物活性, 从而增强了传感器的灵敏度和稳定性, 拓宽了线性响应范围及降低了检测下限.     

DNA在Mg/聚2,6-吡啶二甲酸膜上的固定和杂交及其PAT基因片段的电化学阻抗谱测定

以静电吸附法使Mg²⁺修饰于玻碳电极(GCE)上电聚合的2,6-吡啶二甲酸膜(PDC)上, 制得的Mg/PDC/GCE电极, 成为DNA固定及杂交的良好平台. 应用微分脉冲伏安法和电化学阻抗谱对DNA的固定和杂交进行表征. 以电化学阻抗谱免标记法检测目标DNA比以亚甲基蓝为指示剂的微分脉冲伏安法有更高的灵敏度. 固定于电极表面的DNA探针与互补单链DNA杂交后使电负性的[Fe(CN)₆]^3-/4-的表面电子传递电阻值显著增大, 以此作为检测信号可以高灵敏度地测定目标DNA. 电化学阻抗谱检测转基因植物外源PAT基因片段, 线性范围为1.0×10^-9 ~ 1.0×10^-5 mol/L, 检测限为3.4×10^-10 mol/L.     

超细氢氧化亚镍的溶胶凝胶法制备及其准电容特性

以聚乙二醇为抑制剂,采用溶胶凝胶法制备了粒径小于200 nm且具有链珠状特殊形态的超细氢氧化亚镍电极材料.伏安特性测试和电化学阻抗测试表明在氢氧化亚镍中掺加适量碳纳米管可以显著改善电极材料的容量特性和阻抗特性,其中碳纳米管质量分数为20％的复合电极其比电容量可以达到320 F&;#8226;g^－1.采用复合电极作为正极,活性炭电极作为负极组成的复合型电化学电容器最大工作电压可以达到1.6 V,具有良好的容量特性和大电流放电特性.恒流充放电测试证明复合型电化学电容器具有高能量密度及高功率放电特性,电容器的峰值功率密度为8.6 W&;#8226;g^－1.当以0.88 W&;#8226;g^－1功率放电时,电容器能量密度可达20.11 W&;#8226;h&;#8226;kg^－1, 当采用3.46 W&;#8226;g^－1的高功率进行放电时,复合型电容器的能量密度仍然能够达到11.11 W&;#8226;h&;#8226;kg^－1.     

乙烯/臭氧/水气相反应体系羟甲基过氧化氢产生机理及其动力学

在室温(298±2 K)、大气压(1´10⁵ Pa)条件下研究了乙烯/臭氧/水反应体系中羟甲基过氧化氢(HOCH₂OOH, HMHP)产生机理及其动力学. 反应物采用长光路Fourier红外光谱(LP-FTIR)原位测定. HMHP经低温采集后利用高压液相色谱(HPLC)柱后荧光技术测定. 模式拟合得到的CH₂O₂+H₂O→HMHP(R3)速率常数(k₃)介于(1.6~6.0)×10^−17 cm³·molecule^−1·s^−1. 另外, 采用密度泛函理论在QCISD(T)/6-311+(2d,2p)//B3LYP/6-311+G(2d,2p)水平得到反应(R3)势能面及内禀反应坐标的基础上, 应用Polyrate 程序计算得到了298 K下该反应的经典过渡态理论(TST)速率常数k^TST和正则变分过渡态理论(CVT)速率常数k^CVT, 并应用小曲率隧道效应模型(SCT)对k^CVT进行了校正, 得到了经小曲率隧道效应校正后的速率常数k^CVT/SCT, 分别为2.47×10^−17, 2.47×10^−17和5.22×10^−17 cm³·molecule^−1·s^−1, 与模式拟合得到的结果基本一致.     

螺吡喃衍生物在固相基质中的应用

合成了一种新的螺吡喃衍生物, 将其应用到PVC膜固相基质中, 用于Zn²⁺的荧光检测. 优化条件下, 该敏感膜对Zn²⁺的响应范围为4.94×10^−7~4.15×10^−4 mol·L^−1, 检测限为1.51×10^−7 mol·L^−1. 实验发现, 该敏感膜具有很好的光学稳定性、重现性和可逆性, 而且与其他过渡金属离子如Hg²⁺, Cd²⁺, Pb²⁺, Cu²⁺, Fe³⁺或碱金属和碱土金属离子相比, 该敏感膜对Zn²⁺的荧光增强具有高选择性.     

NO2在NaCl表面的非均相反应研究

采用新的样品制备方法和气-固自由扩散的实验方式, 使用漫反射傅立叶转换红外光谱原位反应器, 结合离子色谱、X-射线光电子能谱、扫描电子显微镜等分析方法, 研究了NO₂在NaCl表面的非均相反应. 研究表明反应不只是发生在颗粒物表面, 体相也参与了反应; 颗粒物表面的活性点对反应起决定作用, 同时测定了反应级数为二级, 反应摄取系数为(1.54±0.70)× 10NO^−5.     

A Novel Electrogenerated Chemiluminescence Reaction Scheme Using Core-Shell LuminoI-Based SiO2 Nanoparticles as a Regulator and Its Analytical Application

A novel core-shell luminol-based SiO2 nanoparticle While these nanoparticles were used as electrogenerated was synthesized by two step micro-emulsion method. chemiluminescence （ECL） reagent, the electrochemical （EC） reaction as well as the subsequent chemiluminescence （CL） reaction not only could be separated spatially, but also presented high efficiency for analytical purpose. In this case, the core-shell luminol-based SiO2 nanoparticles offered more potential to avoid the contradiction between the EC and the CL reaction conditions. A new ECL method based on the nanoparticle was developed, and isoniazid was selected as a model analyte to illustrate the characteristics of this new ECL method. Under the selected conditions, the proposed ECL response to isoniazid concentration was linear in the range of 1.0 ×10^-10 to 1.0 × 10^-6 g/mL with 2 × 10^-11g/mL detection limit.     

Highly Sensitive Electrogenerated Chemiluminescence Isoniazid with NiO Nanoparticles‐modified Graphite Electrode

Abstract

NiO nanoparticles (NiO NPs) were prepared with chemical precipitation method and modified on the surface of vaseline‐impregnated graphite electrode with chitosan. It was found that, based on the catalysis of the NiO NPs for the chemiluminescent reaction of the ECL process, the enhancing effect of isoniazid on the weak electrogenerated chemiluminescence (ECL) signal of luminol at a NiO NPs‐chitosan modified electrode was stronger than that at a bare graphite electrode. Under the optimum experimental conditions, the relative ECL intensity was linear with isoniazid concentration over the range 3.0×10^?10～1.0×10^?6 g/ml at the NiO NPs‐chitosan modified electrode with a detection limit of 1.0×10^?10 g/ml.     

Electrogenerated chemiluminescence aptamer-based biosensor for the determination of cocaine

A novel electrogenerated chemiluminescence aptamer-based (ECL-AB) biosensor for the determination of a small molecule drug is designed employing cocaine-binding aptamer as molecular recognition element for cocaine as a model analyte and ruthenium complex served as an ECL label. A 5′-terminal cocaine-binding aptamer with the ECL label at 3′-terminal of the aptamer was utilized as an ECL probe. The ECL-AB biosensors were fabricated by immobilizing the ECL probe onto a gold electrode surface via thiol-Au interactions. An enhanced ECL signal is generated upon recognition of the target cocaine, attributed to a change in the conformation of the ECL probe from random coil-like configuration on the probe-modified film to three-way junction structure, in close proximity to the sensor interface. The integrated ECL intensity versus the concentration of cocaine was linear in the range from 5.0 × 10⁻⁹ to 3.0 × 10⁻⁷ M. The detection limit was 1.0 × 10⁻⁹ M. This work demonstrates that the combination of a highly binding aptamer to analyte with a highly sensitive ECL technique to design ECL-AB biosensor is a great promising approach for the determination of small molecule drugs.     

Ultrasensitive Eletrogenerated Chemiluminescence Immunoassay by Magnetic Nanobead Amplification

An ultrasensitive electrogenerated chemiluminescence (ECL) immunoassay was proposed by using magnetic nanobeads (MNBs) as the carrier of ECL labels for ECL emission amplification. Carcinoembryonic antigen (CEA) and MNBs were initially immobilized on a platform in 1 : 1 molar ratio via sandwich immunoreaction. Subsequently, the MNBs were released from the platform and labeled with Ru(bpy)₃²⁺ species. After the MNBs with Ru(bpy)₃²⁺ were immobilized on an Au electrode, ECL of the Ru(bpy)₃²⁺ was measured for CEA determination. A linear relation between the ECL intensity and CEA concentration was obtained in a range of 1×10^?14 to 3×10^?13 mol/L (2.0 to 60 pg/mL) with a limit of detection of 8.0×10^?15 mol/L (1.6 pg/mL).     

以Co2＋掺杂纳米TiO2为光催化氧化剂的原位光致化学发光分析方法 研究及其应用

研究了Co2＋掺杂TiO2纳米粒子在光信号诱导下产生的超氧阴离子自由基在纳米粒子表面的吸附和解吸特性. 当以该纳米粒子为光催化氧化剂进行原位光致化学发光反应时, 光诱导产生的超氧阴离子自由基通过扩散穿过纳米粒子表面的双电层到达本体溶液, 与溶液中的化学发光试剂进行化学发光反应. 由于超氧阴离子自由基在纳米粒子表面的吸附、解吸和双电层效应, 使得光化学反应和其后的光生氧化剂的化学发光反应具有时间和空间的分辨特性. 将 Co2＋掺杂TiO2纳米粒子光致化学发光反应的特点与鲁米诺化学发光体系结合, 建立了一种原位光致化学发光反应的新方法, 并提出了一种基于纳米技术调控化学发光反应的新思路. 在最佳反应条件下, 该方法对格列本脲响应的线性范围为2.0×10－8～1.0×10－6 g•mL－1, 检出限为6×10－9 g•mL－1.     

Electrogenerated chemiluminesence method for the determination of riboflavin at an ionic liquid modified gold electrode

A highly sensitive electrogenerated chemiluminescence (ECL) method for the determination of riboflavin was developed based on the enhancement of ECL intensity of lucigenin at room temperature ionic liquids (RTILs) modified gold electrode. RTILs modified gold electrode exhibited excellent electrochemical and ECL property to lucigenin system and the ECL intensity of lucigenin was greatly enhanced by riboflavin. The characterization of the RTILs modified electrode and the attractive performance of the sensitive ECL method for the determination of riboflavin were investigated. Under the optimized conditions, the ECL intensity was directly proportional to the concentration of riboflavin in the range from 5.0×10(-10) g/mL to 1.0×10(-8)g/mL with the detection limit of 1×10(-10) g/mL. The method has been applied to the determination of riboflavin in the pharmaceutical preparations with satisfactory recovery from 96% to 101%. This work demonstrates that the incorporation of ECL method with RTILs modified electrode is a promising strategy for the determination of organic compounds with high sensitivity and good reproducibility.     

Electrogenerated Chemiluminescence Ethanol Biosensor Based on Carbon Nanotube‐Titania‐Nafion Composite Film

Mesoporous titania‐Nafion composite doped with carbon nanotube (CNT) has been used for the immobilization of tris(2,2′‐bipyridyl)ruthenium(II) (Ru(bpy)₃²⁺) and alcohol dehydrogenase on an electrode surface to yield a highly sensitive and stable electrogenerated chemiluminescence (ECL) ethanol biosensor. The presence of CNT in the composite film increases not only the sensitivity of the ECL biosensor but also the long‐term stability of the biosensor. The present biosensor responds linearly to ethanol in the wide concentration ranges from 1.0×10^?5 M to 1.0×10^?1 M with a detection limit of 5.0×10^?6 M (S/N=3). The present ECL ethanol biosensor exhibited higher ECL response compared to that obtained with the ECL biosensor based on the corresponding composite without CNT. The present CNT‐based ECL biosensor showed good long‐term stability with 75% of its initial activity retained after 2 weeks of storage in 50 mM phosphate buffer at pH 7.0.     

高效液相色谱化学发光法检测牛奶中残留四环素类化合物的研究

基于四环素类抗生素药物中的四环素(TC)、土霉素(OTC)、金霉素(CTC)和多西环素(DC)能够强烈增敏通过恒电流电解方法在线电生BrO^－和鲁米诺之间产生的化学发光, 提出了一种高效液相色谱(HPLC)化学发光(CL)法检测4种四环素类抗生素药物的新方法. 以Nucleosil RP-C₁₈ (250 mm×4.6 mm, i.d., 5 μm, pore size, 100 Å)为色谱柱, 0.05 mol• L^－1磷酸二氢钾(pH 2.5)-乙腈(30∶70, V∶V)为流动相, 流速1.2 mL/min, 柱温25 ℃, 同时分离检测四种抗生素的总时间为11 min. 研究并优化了流动相、电生试剂化学发光检测的条件. 四种抗生素的检出限为0.002～0.008 μg•mL^－1 (3σ), 对0.01 μg•mL^－1的四种抗生素测定的相对标准偏差为2.0%～3.6% (n＝11). 该方法已成功应用于牛奶中残留四环素类抗生素含量的分析.     

Keggin型缺位磷钨杂多阴离子的电化学性质及电催化还原过氧化氢

循环伏安实验显示, 缺位磷钨杂多阴离子 的酸性水溶液在玻碳(GC)电极上有两对可逆的还原-氧化波. 第一对波的电荷迁移数为1.4, 有2个质子参与反应; 第二对波的电荷迁移数为1.0, 参加电极反应的质子数为1. 根据峰电流与电位扫描速率平方根的关系得到 在0.1 mol•L－1 NaOAc＋HOAc溶液中的扩散系数 Do为3.54×10－6 cm2•s－1. 交流伏安和交流阻抗实验表明, 的电极过程包含吸附和脱附步骤, 第一对波的电荷迁移阻抗较大, 第二对波的较小, 对应的交换电流密度i0分别为4.6×10－5和6.7×10－4 A•cm－2. 电极过程的可逆性及其缺位特性使它对H2O2的还原有显著的电催化作用, 因此有望用于有机物的氧化和降解. 同时, 还提出了一个相关的电催化机理.