The synthesis of bis(benzo-15-crown-5) derivatives and their use in potassium-PVC membrane electrodes

Five new bis(benzo-15-crown-5) derivatives with different connecting groups were synthesized. Potassium ion-selective PVC membrane electrodes based on these bis(crown ether)s were prepared and their selective properties were measured. The results showed that most of these electrodes are stable over a wide pH range and their selectivity coefficients were better than those of an electrode based on natural valinomycin.     

Ion-selective electrodes for gold and silver determination

Some new ion-selective electrodes for silver and gold are described. They are based on the ion-associate species formed by the cyanide, chloride or thiourea complexes of the metals, with hydrophobic anions or cations, as appropriate. The electrodes have been applied to the determination of gold and silver in various technological process solutions in industry.     

A novel high-performance fourier transform ion cyclotron resonance cell for improved biopolymer characterization

A new trapped ion cell design for use with Fourier transform ion cyclotron resonance mass spectrometry is described. The design employs 15 cylindrical ring electrodes to generate trapping potential wells and 32 separately assignable rod electrodes for excitation and detection. The rod electrodes are positioned internal to the ring electrodes and provide excitation fields that are thereby linearized along the magnetic field over the entire trapped ion volume. The new design also affords flexibility in the shaping of the trapping field using the 15 ring electrodes. Many different trapping well shapes can be generated by applying different voltages to the individual ring electrodes, ranging from quadratic to linearly ramped along the magnetic field axis, to a shape that is nearly flat over the entire trap volume, but rises very steeply near the ends of the trap. This feature should be useful for trapping larger ion populations and extension of the useful range of ion manipulation and dissociation experiments since the number of stages of ion manipulation or dissociation is limited in practice by the initial trapped ion population size. Predicted trapping well shapes for two different ring electrode configurations are presented, and these and several other possible configurations are discussed, as are the predicted excitation fields based on the use of rod electrodes internal to the trapping ring electrodes. Initial results are presented from an implementation of the design using a 3.5 T superconducting magnet. It was found that ions can be successfully trapped and detected with this cell design and that selected ion accumulation can be performed with the utilization of four rods for quadrupolar excitation. The initial results presented here illustrate the feasibility of this cell design and demonstrate differences in observed performance based upon different trapping well shapes.     

New Electrodes with Membranes Based on Semiconductor Compounds of the AIIIBV Type

The characteristics of new electrodes with semiconducting membranes based on gallium arsenide and gallium antimonide were studied in solutions of metal salts, halides, and complexing agents. The proposed electrodes can be used as indicator electrodes in acid–base, precipitation, and complexometric potentiometric titration.     

新型有机太阳电池塑料薄膜化的研究进展

染料敏化纳米晶太阳电池被认为是一种能够代替硅太阳电池的新型电池。本文介绍这一有机太阳电池塑料薄膜化的研究进展,重点论述了4种半导体电极的低温成膜方法,即压力法、水热合成法、微波照射法和电泳沉积法;介绍了对电极塑料薄膜化的研究成果并阐述了塑料薄膜太阳电池的开发现状及今后的研究动向。     

Integrated electrochemical transistor as a fast recoverable gas sensor

A new design of conductometric chemical sensors based on conducting polymers as chemosensitive elements was suggested. The sensor includes six electrodes. Four inner electrodes coated by chemosensitive polymer are used for simultaneous two- and four-point resistance measurements thus providing information on the bulk polymer resistance and on the resistance of the polymer/electrode contacts. Two outer electrodes wired to inner electrodes by polymeric electrolyte are used for electrical control of redox state of the chemosensitive polymer. The outer electrodes are connected to potentiostat as reference and counter electrodes. It allows us to control redox state of the inner (working) electrodes. This new measurement configuration, resembling chemosensitive electrochemical transistors, provides an internal test of the sensor integrity and an electrically driven sensor regeneration. It was tested as a sensor for the detection of nitrogen dioxide. Polythiophene or polyaniline was used as receptors. Cyclic voltammograms of these polymers on the sensor surface measured in air atmosphere were very similar to that measured in aqueous electrolyte. A control of conductivity of these chemosensitive polymers by electrical potential applied vs. incorporated reference electrode was demonstrated. This effect was used for the regeneration of the chemosensitive material after exposure to nitrogen dioxide: in comparison to usual chemiresistors displaying an irreversible behavior in such test even in the time scale of hours, a completely reversible sensor regeneration within few minutes was observed.     

A Calculation Method Based on Amperometric Titration with Two Indicator Electrodes

A new calculation method was proposed for determining substances by amperometric titration with two indicator electrodes. The model is based on the modified Dalahay equation for reversible redox systems and electrodes of different surface areas.     

载氧化钌碳纳米管超级电容器电极

研究了一种采用溶胶-凝胶方法制备超细氧化钌粉末的新方法，该方法制备的氧化钌电极材料在250 ℃热处理后具有570 F•g－1的比电容量并具有典型的多孔特征.通过在碳纳米管表面化学沉积氧化钌的方法制备了不同成分的氧化钌/碳纳米管复合电极,并探讨了其电化学伏安特性和直流充放电特性.该复合电极具有高能量密度特性，同时还具有良好的高功率放电特性.     

锂空气电池空气电极LiCoO2电催化性能研究

自设计建立锂空气电池实验装置,研究以掺入LiCoO2作为电催化剂的空气正极的电化学性能及其放电前后催化剂结构的变化.循环伏安、XRD及充放电测试等表明,LiCoO2能够很大程度地改善空气电极的放电性能.尤其是在放电前,将掺有LiCoO2的空气正极充电至4.1 V,此时LiCoO2的Co元素呈现较高的价态（Co3＋/Co...     

Effect of lipophylic salts on ise detection limit: application to calixarene-based highly efficient potassium-selective electrodes

A new interpretative model for interpolation of potentiometric data from liquid membrane ion selective electrodes has been formulated; the model allows one to achieve information about partitioning equilibria establishing at the membrane-analysed solution interface of hydrophilic cations present in the membrane as counterions of exchanger lipophylic anions. The fundamental importance of such equilibria is related to their contribution to the detection limit of the electrodes. The soundness of the proposed model was positively verified by employing it in the characterization of new K(+)-selective electrodes based on a calixarenic ionophore. Although the validity of interpolation based on our model does not significantly differ from that obtained with the simpler model providing the inclusion of a constant parameter in the logarithmic argument of Nicolski-Eisenman's equation, the information obtained resulted to be analytically suitable for optimising the membrane composition and, as a consequence, the performance of the electrodes.     

革除或减少增塑剂的敏感膜离子选择电极

基于国内外最新研究工作,系统总结了离子选择电极膜中革除或减少外增塑剂的新膜基体,包括丙烯酸酯类聚合物、羟基功能化的乙烯基树脂、聚氨酯、硅橡胶以及导电聚合物,对其物理化学性能以及传感器检测等进行了全面归纳与讨论.指出该类革除外增塑剂的传感膜不仅避免了增塑剂的泄漏及其对生物样品的污染,而且较传统增塑聚氯乙烯(PVC)膜扩散系数降低了约3个数量级,有利于抑制过膜离子流,使其检测下限较传统增塑PVC下降了5个数量级,且选择系数也有不同程度的改善.另外,该类传感膜材料由于与固体支撑材料间优良的粘附性保证了电极的使用寿命,特别是在微型化固态电极中.以这类传感膜构建的电位型离子传感器将以其独特的优势在环境监测、食品卫生,尤其是在医疗诊断、生物物质检测中展示出不可替代的作用.     

Visible and FTIR Microscopic Observation of Bisthiourea Ionophore Aggregates in Ion‐Selective Electrode Membranes

Since conventional response models for ionophore‐based ISEs are based on the assumption of a homogeneous membrane phase, they cannot accurately predict the response of membranes containing self‐aggregating ionophores. However, meaningful conclusions about the relationship between ionophore structure and potentiometric responses can only be drawn if ionophore aggregation is properly recognized. This study demonstrates that dark field visible microscopy and FTIR microspectroscopy are valuable tools for the observation of such ionophore self‐aggregation and, thereby, the development of new ionophore‐based ISEs. Sulfate selective electrodes with solvent polymeric membranes containing bisthiourea ionophores that differ only by peripheral nonpolar substituents were shown to exhibit very different interferences from the sample pH. On one hand, optimized electrodes based on an ionophore with a phenyl substituent on each thiourea group ( 1 ) do not respond to pH at all and function well as sulfate‐selective electrodes. On the other hand, membranes containing a more lipophilic ionophore with two additional hexyl‐substituted adamantyl groups ( 2 ) exhibit severe pH interference at pH values as low as pH 5. The observation of membranes containing ionophore 2 with dark field visible microscopy and FTIR microspectroscopy shows supramolecular aggregation, and explains the startling difference between the potentiometric responses of the two types of electrodes.     

Metal Complexes as Promising Ionophores for the Production of Anion-Selective Electrodes with Improved Selectivity

The possibility of producing liquid anion-selective electrodes with improved selectivity based on the capability of the metal atom to coordinate the analyzed anions is illustrated using numerous examples. The subjects under consideration were electrodes based on high-stable lipophilic metal complexes with polydentate organic ligands, electrodes based on lipophilic organometallic compounds capable of coordinating anionic ligands, and electrodes based on higher quarternary ammonium salts that respond to lipophilic anionic metal complexes, in particular, the electrodes with the ligand function. The theoretical principles underlying the above electrode operation are discussed. Methods for optimizing the composition of the membrane and of the studied solution are suggested with the aim to improve the selectivity of the electrode.     

Reduced Graphene Sheets Modified Electrodes for Electrochemical Detection of Sulfide

This paper describes a new electrochemical sensor based on reduced graphene sheets (RGSs) modified glassy carbon electrodes for rapid detection of sulfide. The morphology and electrochemical properties of the RGSs are characterized by atomic force microscopy and cyclic voltammetry. The effects of the scan rates and pH are investigated to evaluate the oxidation processes. Analytical performances of RGSs modified electrodes for direct determination of sulfide in phosphate buffer solutions (PBSs) are also assessed. The RGSs are shown to be viable potential material for sulfide detection as shown by their electrochemical performance.     

Studies in the field of electrochemistry of organic compounds in 2000–2006

This review presents the author’s views on the state-of-art in the electrochemistry of organic compounds, based on the analysis of the data published from 2000 to 2006. The number of publications that consider to one or another extent the electrochemical reactions involving organic compounds constantly increases. The range of problems studied is intimately related with the demands of new technologies. The largest number of publications are devoted to the electrochemical polymerization and the properties of polymeric films on the electrode surface and also to the mechanism of electrode reactions of metal-complex compounds and their properties. The directions such as electrochemistry of nanomaterials and the methods of modification of electrodes are largely associated with the use of electroactive polymers. Fine organic electrosynthesis including the technological developments in the destruction of organic compounds, e. g., for cleaning of waste water, fade to the background. A new direction in this field is the development of amperometric sensors that employ modified electrodes based on electrochemically activated polymeric films.     

Quartz Crystal Microbalance with Dissipation Monitoring (EQCM-D) for in-situ studies of electrodes for supercapacitors and batteries: A mini-review

Herein the application of a recently introduced new method of tracking in-situ the intercalation-induced deformations of supercapacitor and Li-battery electrodes is reviewed. The method is based on the use of multi-harmonic electrochemical quartz microbalance with dissipation monitoring, EQCM-D (in-situ hydrodynamic spectroscopy) which enables a permanent control of the electrodes' state-of-health by probing their mechanical properties. The potential-dependent frequency and resonance width changes are fitted to a chosen hydrodynamic admittance model allowing thus quantification of the electrode deformations under different charging conditions. Intercalation of different alkaline metal cations into layered MXene electrode serves as a readily understandable working example of quantifying such electrodes deformations. Further method developments including in-situ viscoelastic characterization of composite porous electrodes are envisaged in the near future.     

High transmission 3D printed flex‐PCB‐based ion funnel

In this study a novel fabrication method for a radio frequency (RF) ion funnel is presented. RF ion funnels are important devices for focusing ion clouds at low vacuum conditions for mass spectrometry or deposition‐related applications. Typically, ion funnels are constructed of stainless steel plate ring electrodes with a decreasing diameter where RF and direct current potentials are applied to the electrodes to focus the ion cloud. The presented novel design is based on a flexible circuit board that serves both as the signal distribution circuit and as the electrodes of the ion funnel. The flexible circuit board is rolled into a 3D printed scaffold to create a funnel shape with ring electrodes formed by the copper electrodes of the flexible circuit board. The design is characterized in direct comparison with a conventional steel‐plate electrode design. The discussed results show that the new funnel has similar performance to the conventionally designed funnel despite much lower manufacturing costs. Copyright © 2015 John Wiley & Sons, Ltd.     

Amperometric enzyme electrodes in analytical chemistry

Summary An overview is given of works on the construction and application of amperometric enzyme electrodes for the determination of metabolites in biological solutions. The following electrodes are dealt with: monoenzyme and polyenzyme electrodes involving amperometric detection of hydrogen peroxide, bienzyme electrodes with oxidase-peroxidase, electrodes based on organic metals and chemically modified electrodes, dehydrogenase electrodes, amperometric hydrolase electrodes and highly sensitive electrodes involving chemical amplification. Biocatalytic stripping and macrokinetic behaviour of the electrodes are discussed.

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Amperometrische Enzymelektroden in der analytischen Chemie

     

Functional layers for chemical sensors based on conducting polypyrrole

Functional thin layers based on polypyrrole were used in electrochemical sensors as mixed conducting interfaces between ion‐selective membranes and the wiring. In particular, new types of ion‐selective electrodes for potentiometric measurement of pH value and concentration of sulfate ions in solutions were developed. The resulting electrodes do not need any inner liquid junction. First determinations of the sensor parameters sensitivity, selectivity and long term stability indicate a good performance of the prepared sensors. The results imply that interfaces, containing polypyrrole, could be an interesting basis for the construction of a new type of all‐solid‐state ion‐selective electrodes.     

Cross-sensitive rare-earth metal sensors based on bidentate neutral organophosphorus compounds and chlorinated cobalt dicarbollide

A new carbon composite electrode material, based on dispersing glassy carbon (GC) microparticles into methyltrimethoxysilane-derived sol, is described in the present paper. The resulting glassy carbon ceramic composite electrodes (GCCEs) combine the electrochemical properties of GC with the advantages of composite electrodes, and thus offer high electrochemical reactivity, low background current and are easy to prepare, modify and renew. The new material has a low double-layer capacitance and a wide potential window. Scanning electron microscopy (SEM) images indicate significant difference in the structure of GCCE and carbon ceramic composite electrode (CCE). The electrochemical properties and advantages of GCCE should find broad utility in electroanalysis.