儿茶酚及其衍生物的性质及应用

儿茶酚类化合物普遍存在于自然界,具有多功能性,可参与大多数生化进程.它具有较强的氧化还原性,pH响应性和显著的螯合性;而且儿茶酚中的邻位羟基可通过多种方式与不同材料相互作用,特别是与三价铁离子具有很强的螯合作用.由于儿茶酚类化合物性质的多样性,其可以存在于单分子体系、超分子体系、金属离子络合体系或通过共价键相连的聚合物.儿茶酚的多功能性使其参与多种自然过程,其作用表现在众多方面,从海洋生物的粘附性到对过渡金属的储存均得力于儿茶酚类化合物.由于儿茶酚性质的多样性,引起研究者们的广泛兴趣,近年来对其研究日益增多,旨在制备新型的功能性材料和涂层.     

铁卟啉修饰电极催化氧化测定儿茶酚类化合物

将铁卟啉氯化－５，１０，１５，２０－四－（－３－甲氧基－４－羟基苯基）卟啉铁（ＴＭＨＰＰ·ＦｅＣｌ）修饰在玻碳电极表面，制备成对儿茶酚类化合物具有高的响应的ＴＭＨＰＰ·ＦｅＣｌ修饰电极。该电极对多巴胺、肾上腺素等儿茶酚类化合物在各自的响应区间内有良好的线性关系，电极具有灵敏度高、响应快、稳定性好等特点。电极响应时间小于１０ｓ，儿茶酚类检测浓度在１０（－６）ｍｏｌ／Ｌ数量级。     

血红素修饰电极电催化氧化测定儿茶酚类化合物

采用循环伏安法将血红素修猸于玻碳电极表面，制备出对儿茶酚类化合物具有电催化氧化作用的血红素修饰电极（Ｈｅｍｅ／ＧＣ）。该电极上的催化氧化峰电流与邻苯二酚、多巴胺、肾上腺素等儿茶酚类化合物的浓度在各自响应的范围内有良好的线性关系，检测下限为４￣８×１０＾－８ｍｏｌ／Ｌ。用于多巴胺和肾上腺素药物针剂的测定结果令人满意，回收率９８￣１０２％。     

毛细管电泳-间接化学发光法分离检测儿茶酚胺及儿茶酚

根据儿茶酚胺及儿茶酚淬灭铁氰化钾-鲁米诺体系发光的原理,利用毛细管电泳．化学发光联用技术分离测定了3种儿茶酚胺和儿茶酚,并优化了检测和分离条件。在最佳条件下,测得多巴胺、肾上腺素、去甲肾上腺素和儿茶酚的检出限分别为0．33、1．8、2、4和0、12μmol／L。本方法具有一定的选择性,对于医用注射液及尿样在未经预处理条件下可直接进行分离分析,结果令人满意。     

分析测试中的试验设计和优化方法 三、均匀设计法

一、引言在上两讲我们已经研究过用正交试验设计来选择分析条件和构造回归方程。正交试验设计利用均衡分散性和整齐可比性从全面试验中选出部分点进行试验,简单比较因素各水平试验指标的平均值估计各因素的效应,减小了试验工作量和计算工作量,而仍能得到基本上反映全面情况的试验结果,是一种优越性很大的试验设计方法。但是当试验中因素数或其水     

含儿茶酚基团的湿态组织粘附水凝胶

湿态粘附作用对于生命的孕育和发展具有重要意义。水凝胶是一类兼具固液特性的智能材料，组织粘附水凝胶因多功能性和生物相容性而被广泛应用于伤口闭合和修复、细胞工程、组织工程等领域。然而，湿态组织表面的水合层阻碍了组织粘附水凝胶与组织表面形成界面粘附键。面对这一挑战，受海洋贻贝足丝蛋白中DOPA的儿茶酚基团是水下粘附的关键结构的启发，含儿茶酚基团的湿态组织粘附水凝胶的研究引起了广泛关注。本综述介绍了贻贝足丝蛋白(Mfps)的结构及湿态粘附机理，并将儿茶酚衍生物分为天然Mfps或利用基因工程合成的Mfps、含儿茶酚基团的小分子化合物、儿茶酚基团改性的天然高分子以及含儿茶酚基团的合成功能高分子；随后，概述近十年含儿茶酚基团的湿态组织粘附水凝胶在组织创口修复材料、生物涂层材料、靶向型药物输送材料、生物电子设备材料的研究进展；文末，展望了此类水凝胶材料未来发展面临的机遇和挑战。     

应用毛细管电泳法分离测定6种取代苯化合物

采用毛细管电泳法对六种取代苯化合物进行了分离研究，考察了3种电泳模式对分离的影响。环糊精的胶束毛细管电泳法可使各组分达到基线分离，正交设计法得到了最佳实验条件，在质量浓度为30－300mg/L的范围内，可进行定量分析，该方法已应用于废液中苯类化合物的测定。     

用正交设计制作酶过程曲线的方法

用正交设计制作酶过程曲线的方法郭慧云，张立，李彬，刘兰英（吉林大学分子生物学系，长春１３００２３）正交设计￣［１］，是用正交表安排多因素试验、用统计数学原理进行数据分析的一种科学方法。为培养学生的实际工作能力，应让本科生在专门化实验课中得到使用该方法...     

脉冲色谱法测定金属铬中的氢

本文采用脉冲色谱法温室金属铬合中的氢含量，用正交试验法选择了最佳分析条件（含加热时间，加热初级电流，试样重量，浴料及浴比），建立了锡浴法测定铬中氢的方法，方法精度为５．５％。     

合成苯并咪唑类化合物的工艺改进

邻苯二胺磷酸盐与脂肪酸在无溶剂的条件下回流反应合成了苯并咪唑类化合物,其结构经IR确证。正交试验确定最佳反应条件为:邻苯二胺50 mmol,n(邻苯二胺):n(甲酸)=1.0:1.5,磷酸4 g,回流反应7 h。在最佳反应条件下做放大实验,产率89.3%。     

A mushroom (Agaricus bisporus) tissue homogenate based alcohol oxidase electrode for alcohol determination in serum

To construct homogenized tissue based biosensors by using plant tissue materials is a relatively new development in the biosensor technology. In this study, a homogenized mushroom (Agaricus bisporus) tissue based electrode in which alcohol oxidase activity was developed by immobilizing with gelatin and cross-linking agent glutaraldehyde at dissolved oxygen probe for determination of ethyl alcohol. The electrode response depends linearly on ethyl alcohol concentration between 0.2 and 20 mM. In the optimization studies, phosphate buffer (pH 7.5, 50 mM) and 35 degrees C were obtained as the optimum conditions. By using the electrode prepared we have made approximately 60 measurements in 10-h period, and response time of the electrode is 2 min for each measurement.     

Differential anodic oxidation of single organic linkage molecules enabling orthogonal bio-immobilization

We report a novel method for preparing electrode surfaces that present thiol-containing or thiol-reactive groups using a single organic silane linkage terminated with 1,3-dithiane via differential anodic oxidation of 1,3-dithiane. We found that the surface groups resulting from the anodic oxidation reaction differed according to the concentration of H₂O in the electrolyte solution during the oxidation reaction. The differential anodic oxidation was used successfully for the orthogonal immobilization of two different proteins. We demonstrated also the preparation of an immunoassay platform via orthogonal immobilization, which was then used to detect multiple target antigens based on a sandwich immunoassay.     

Nanobiocomposite Modified Carbon‐Ceramic Electrode Based on Nano‐TiO2‐Plant Tissue and Its Application for Electrocatalytic Oxidation of Dopamine

A new modified carbon‐ceramic electrode was prepared by incorporating TiO₂ nanoparticle into sol‐gel network by accompanying apple tissue. A mixture of fine graphite powder with 15 wt% of TiO₂ nanoparticle was used for the preparation of the carbon matrix and finally modification with a known amount weighted of apple tissue. The apple tissue containing polyphenol oxidase enzyme acts as molecular recognition element. The electrocatalytic oxidation of dopamine was investigated on the surface of the nanobiocomposite modified carbon‐ceramic electrode using cyclic voltammetry, chronoamperometry and amperometry techniques. Effect of pH, scan rate, TiO₂ percentage on the response of modified electrode was studied. The prepared modified electrode presented a linear range for dopamine from 5.0×10^?6 to 1.2×10^?3 M in buffered solutions with pH 7.4 by amperometry. The detection limit was 3.41×10^?6 M dopamine. The response of the modified carbon‐ceramic electrode and unmodified carbon‐ceramic electrode was compared.     

正交表诸因素对铁电极充电效率的影响

铁镍蓄电池具有理论比能量高,原材料丰富,价廉,环保等优点.它有良好的应用前景.本文概述了铁镍电池现有的优点、缺点和铁电极的制作方法.本文通过正交实验探讨不同因素对铁电极充电效率的影响,着重讨论了电解质溶液中添加剂对铁电极充电效率的影响.在本文中铁电极充电效率从30%~60%被提高到80%,这将有助于实现铁镍电池的密封.     

邻菲咯啉冠醚衍生物为载体的伯胺药物电极及机理研究

合成了邻菲咯啉-18-冠-6等四种含邻菲咯啉结构的冠醚化合物, 并用作载体制备伯胺电极, 以苄胺为模型化合物, 研究了电极特性, 并制备了测试美西律药物的选择性电极。研究了实验条件对电极性能的影响。用正交多项式回归法优化电极的膜组成。苄胺电极的线性范围1.0×10^-5~0.1mol/L, 斜率55.6mV/pc, 检测下限2.0×10^-6mol/L。美西律电极的线性范围6.0×10^-6~0.1mol/L, 检测下限8.0×10^-7mol, 斜率58.0mV/pc。同时研究了冠醚推动伯胺穿透大块液膜的传输行为。     

Ti/α-PbO2/β-PbO2电极电化学降解2-氯酚

采用电化学沉积法在Ti基底上制备了复合电极Ti/α-PbO2/β-PbO2,扫描电镜结果表明电极呈现由β-PbO2小晶体组成的菜花状微观形貌.所制电极在电化学降解环境污染物2-氯酚时表现出较高的电催化效率、较好的电极稳定性和较长的电极寿命.用正交实验优化了电化学降解2-氯酚的实验条件.在最优的实验条件(2-氯酚初始浓度50 mg/L,电解质0.1 mol/L Na2SO4,温度35oC,阳极电流密度20 mA/cm2)下电化学降解180 min后,2-氯酚的去除率达100%.动力学结果表明, Ti/α-PbO2/β-PbO2电极上2-氯酚的电化学氧化符合准一级动力学过程.     

Construction and Application of a PVC Membrane Enoxacin Ion－selective Electrode Based on a Needle－shaped Inner Reference Electrode

IntroductionPVC membrane- coated- wire electrodes areused in the analytical field widely. They are pre-pared usually with platinum wire,silver wire orgraphite rod coated with a PVC thin membranecontaining various active components and plasticiz-ers[1— 3 ] .The electrodes have no inner KCl solutionand they are notinfluenced by the sample pressure.Furthermore,they are free from directional selec-tivity when they are installed,and they can be mi-crominiaturized easily. The shortcomings of th…     

Plant tissue-based amperometric electrode for eliminating ascorbic acid interferences

An application of tissue-based electrodes aimed at eliminating interferences from co-existing electroactive constituents is described. The concept is illustrated using a zucchini-containing carbon paste electrode. The presence of the enzyme ascorbic acid oxidase (AAO) in the zucchini tissue effectively eliminates contributions from ascorbic acid, thus allowing selective measurement of dopamine or norepinephrine. In comparison with analogous enzyme-based AAO electrodes, the tissue “eliminator” electrode offers high biocatalytic stability and activity and extremely low cost. The effects of various experimental variables are studied using pulse voltammetry, chronoamperometry and flow-injection amperometry. The electrode has a useful lifetime of 4 weeks. Simultaneous elimination of uric acid interferences is obtained via the co-immobilization of uricase. Oxygen background currents are eliminated in the presence of ascorbic acid.     

Anisotropic Conductivity at the Single‐Molecule Scale

In most junctions built by wiring a single molecule between two electrodes, the electrons flow along only one axis: between the two anchoring groups. However, molecules can be anisotropic, and an orientation‐dependent conductance is expected. Here, we fabricated single‐molecule junctions by using the electrode potential to control the molecular orientation and access individual elements of the conductivity tensor. We measured the conductance in two directions, along the molecular plane as the benzene ring bridges two electrodes using anchoring groups (upright) and orthogonal to the molecular plane with the molecule lying flat on the substrate (planar). The perpendicular (planar) conductance is about 400 times higher than that along the molecular plane (upright). This offers a new method for designing a reversible room‐temperature single‐molecule electromechanical switch that controllably employs the electrode potential to orient the molecule in the junction in either “ON” or “OFF” conductance states.     

Electrocatalytic detection of thiols using an edge plane pyrolytic graphite electrode

The first example of using an edge plane pyrolytic graphite electrode in electroanalysis is reported as the determination of homocysteine, N-acetylcysteine, cysteine and glutathione is studied. The response of the electrode in the direct oxidation of thiol moieties is explored and found to be electrocatalytic producing a reduction in the overpotential while having enhanced signal-to-noise characteristics compared to glassy carbon and basal plane pyrolytic graphite electrodes. The effectiveness of the methodology is examined in the determination of cysteine species in a growth tissue media that contains a high number of common biological interferences. The advantageous properties of this electrode for thiol determination lie in its excellent catalytic activity, sensitivity and simplicity.