电化学生物传感器在环境监测中的应用及发展前景

简要介绍了电化学生物传感器的工作原理,重点论述了电化学生物传感器在环境监测领域的应用及其研究进展,主要包括水环境污染物和大气污染物的监测,以及农药残留的监测等.同时,对电化学生物传感器的发展方向及前景进行了展望.     

Physicochemical and electrochemical properties of sulfolane solutions of lithium salts

The physicochemical and electrochemical properties (electrical conductivity, viscosity, density, and electrochemical stability) of sulfolane solutions of various lithium salts are studied. The nature of the anion considerably affects the physicochemical and electrochemical properties of the electrolyte systems considered. Sulfolane solutions of lithium salts have moderate electrical conductivity and high electrochemical stability, and can be used as electrolytes in lithium batteries.     

Stretchable Electrochemical Sensor for Real‐Time Monitoring of Cells and Tissues

Stretchable electrochemical sensors are conceivably a powerful technique that provides important chemical information to unravel elastic and curvilinear living body. However, no breakthrough was made in stretchable electrochemical device for biological detection. Herein, we synthesized Au nanotubes (NTs) with large aspect ratio to construct an effective stretchable electrochemical sensor. Interlacing network of Au NTs endows the sensor with desirable stability against mechanical deformation, and Au nanostructure provides excellent electrochemical performance and biocompatibility. This allows for the first time, real‐time electrochemical monitoring of mechanically sensitive cells on the sensor both in their stretching‐free and stretching states as well as sensing of the inner lining of blood vessels. The results demonstrate the great potential of this sensor in electrochemical detection of living body, opening a new window for stretchable electrochemical sensor in biological exploration.     

Carbon nanotube and diamond as electrochemical detectors in microchip and conventional capillary electrophoresis

As two important polymorphs of carbon, carbon nanotube (CNT) and diamond have been widely employed as electrode materials for electrochemical sensing. This review focuses on recent advances and the key strategies in the fabrication and application of electrochemical detectors in microchip and conventional capillary electrophoresis (CE) using CNT and boron-doped diamond. The subjects covered include CNT-based electrochemical detectors in microchip CE, CNT-based electrochemical detectors in conventional CE, boron-doped diamond electrochemical detectors in microchip CE, and boron-doped diamond electrochemical detectors in conventional CE. The attractive properties of CNT and boron-doped diamond make them very promising materials for the electrochemical detection in microchip and conventional CE systems and other microfluidic analysis systems.     

Electrochemical Properties of Vanadium Oxide Aerogels and Aerogel Nanocomposites

The electrochemical properties of high surface area transition metal oxide aerogels are extremely interesting because aerogels serve to amplify surface effects. As a result, the electrochemical properties are dominated by surfaces rather than by bulk behavior. In the case of vanadium oxide aerogels this leads to extraordinary electrochemical properties, including an extremely high capacity for lithium and electrochemical responses that are both battery-like and capacitor-like. By exploiting sol-gel synthesis, it is possible to synthesize nanocomposite electrodes in which aerogels are in intimate contact with carbon nanotubes. The resulting nanocomposites exhibit superior electrochemical properties, especially at high discharge.     

电化学处理对神木煤显微组分表面结构及可浮性的影响研究

为建立煤岩显微组分的电化学浮选分离方法,以铝为电极,考察了阳极和阴极电化学处理对神木煤镜质组和惰质组表面结构及表面电位和润湿性的影响规律。结果表明,电化学处理对煤岩显微组分表面-OH、-COOH等含氧官能团影响显著;阳极处理使显微组分表面zeta电位向负电方向偏移,且润湿性增加,阴极处理则使其向正电方向偏移,润湿性减小;阳极处理后镜质组接触角的变化趋势更为显著,而阴极处理对于惰质组的影响更为明显。     

Graphene Nanoplatelets: Electrochemical Properties and Applications for Oxidation of Endocrine‐Disrupting Chemicals

In most graphene‐based electrochemical applications, graphene nanoplatelets (GNPs) have been applied. Now, for the first time, electrochemical properties of GNPs, namely, its electrochemical activity, potential window, and double‐layer capacitance, have been investigated. These properties are compared with those of carbon nanotubes (CNTs). GNP‐ and CNT‐coated electrodes were then applied for electrochemical oxidation of endocrine‐disrupting chemicals. The GNP‐coated electrode was characterized by atomic force microscopy and electrochemical techniques. Compared with the CNT‐coated electrode, higher peak current for the oxidation of 4‐nonylphenol is achieved on the GNP‐coated electrode, together with lower capacitive current. Electrochemical oxidation of 2,4‐dichlorophenol, bisphenol A, and octylphenol in the absence or presence of 4‐nonylphenol was studied on the GNP‐coated electrode. The results suggest that GNPs have better electrochemical performance than CNTs and are thus more promising for electrochemical applications, for example, electrochemical detection and removal of endocrine‐disrupting chemicals.     

Bio-electrocatalysis of NADH and ethanol based on graphene sheets modified electrodes

Characterization and application of graphene sheets modified glassy carbon electrodes (graphene/GC) have been presented for the electrochemical bio-sensing. A probe molecule, potassium ferricyanide is employed to study the electrochemical response at the graphene/GC electrode, which shows better electron transfer than graphite modified (graphite/GC) and bare glassy carbon (GC) electrodes. Based on the highly enhanced electrochemical activity of NADH, alcohol dehydrogenase (ADH) is immobilized on the graphene modified electrode and displays a more desirable analytical performance in the detection of ethanol, compared with graphite/GC or GC based bio-electrodes. It also exhibits good performance of ethanol detection in the real samples. From the results of electrochemical investigation, graphene sheets with a favorable electrochemical activity could be an advanced carbon electrode materials for the design of electrochemical sensors and biosensors.     

The Effect of Electrochemical and Gas Phase Activation of High Surface Area Carbon Black Ketjen Black EC 600 DJ on Its Surface Composition,Electrochemical Capacitance,and Stability

The effect of electrochemical and gas-phase activation of high-surface-area carbon black Ketjen Black EC 600 DJ on its stability and electrochemical capacitance is studied. The electrochemical activation is carried out according to the “start–stop” protocol (1–1.5 V, 0.5 V/s). The stability of samples is assessed based on variation of their effective resistance (based on the results of cyclic voltammetry (CVA)) and electrochemical capacitance (based on CVA and galvanostatic data) with the cycle number. The changes in the texture and surface properties of activated samples are studied by the methods of nitrogen low-temperature adsorption and X-ray photoelectron spectroscopy. The gas-phase activation of high-surface-area carbon black Ketjen Black EС 600 DJ is shown to impair its stability, while the electrochemical oxidation of carbonblack samples leads to a considerable (two-fold) increase in their electrochemical capacitance.     

Fabrication and Characterization of a Thin-Layer Electrochemical Flow Cell and Its Application for Flow Analysis

The design and fabrication of a home-made thin-layer electrochemical flow cell are reported. The performance and electrochemical characteristics of thin-layer cells are evaluated in terms of flow rate and channel thickness. The adaptability of the flow cell for amperometric and electrochemiluminescence measurements is demonstrated. Also, a flow injection method comprising electrochemical generation followed by spectrophotometric detection is proposed for determination of bromide using the fabricated cell. The influence of chemical, electrochemical, and flow parameters on the absorbance and current signals are investigated, and under optimized conditions, the analytical features of the proposed method with respect to bromide detection are evaluated.     

水滑石的合成及修饰电极的电化学行为

采用共沉淀法合成了摩尔比为3∶1的镍铝、钴铝、镁铝碳酸型水滑石。采用循环伏安法对其所修饰的玻碳电极的电化学行为进行了研究,结果表明仅有镍铝水滑石所修饰的玻碳电极具有较好的电化学行为。     

Nomenclature, symbols and definitions in electrochemical engineering (IUPAC Recommendations 1993)

This document treats performance parameters in electrochemical engineering. Nomenclature and definitions for electrochemical engineering together with the respective symbols are given. Parameters to account for electrochemical reactions in electrolysis as well as for electrochemical power sources (electrochemical energy generators) are included in this document.     

环糊精及其包结物的电化学研究及应用

本文概述了近年来环糊精及其包结物的电化学研究及应用，同时介绍了我们实验室开展的关于环糊精电化学研究的一些工作。     

Characterizations of nickel mesh and nickel foam current collectors for supercapacitor application

Nickel (Ni) current collectors having a three-dimensional and porous structure are considered attractive contestants for high-efficiency supercapacitors. Therefore, Ni current collectors have a unique architecture and outstanding electrochemical properties. This study reports the effect of electrochemical characterizations on the electrochemical behavior and physical properties of Ni mesh and Ni foam. Cyclic voltammetry (CV) and galvanostatic charge discharge (GCD) are used to examine the electrochemical properties and life span of the Ni mesh and Ni foam as a current collector in a supercapacitor application. Structural and microstructural characterizations are performed to verify the formation of an oxide layer after 1000 cycles of CV analysis. Results show that Ni foam can increase the yield electrochemical performance of the supercapacitor. Ni foam present better efficiency (35 F g⁻¹) compared to the Ni mesh (12 F g⁻¹) at 10 mV s⁻¹ scan rate by using 2 mg imaginary mass of active material. This result shows that Ni foam has good electrochemical performance and reversibility, higher pseudocapacitance, weaker polarization, and enhance rotating performance as to Ni mesh. The porous structure of Ni foam is in control for improving of the electrochemical properties, therefore, the electrochemical region was increased and shortened ion diffusion. Structural analysis shows that Ni mesh and Ni foam are oxidized after the electrochemical analysis and transformed to nickel oxide hydroxide (NiOOH). Higher specific surface area between the electrode and electrolyte leads to excellent electrochemical and pseudocapacitive performance of the Ni foam compared to the Ni mesh, even if the materials of current collectors are the same. Hence, the physical structure of the current collectors have a critical part in improving the energy density of the supercapacitor.     

Structure, Properties, and Application of Lithium–Manganese Spinels

Literature data of the past 15 years on the physicochemical and electrochemical properties of Li–Mn spinels are reviewed. Physicochemical characteristics of stoichiometric and defected spinels, chemical deintercalation of lithium out of spinels, electrochemical processes in spinels, syntheses of spinels with improved electrochemical characteristics, and doped spinels are perused.     

A comparison of the electrochemical stabilities of metal,polymer and graphite coated nanospray emitters

Chronoamperometry (CA) and cyclic voltammetry (CV) were used to compare the electrochemical behavior of metal, polymer and graphite coated nanospray emitters. It is shown that electrochemical reactions occurring at the emitter surface limit the lifetime of the noble metal coated nanospray emitters while the graphite coated nanospray emitters show good electrochemical stabilities. Although the surface of the graphite coated emitters may be passivated at positive potentials, the conductive coating is not lost as for the noble metal coated nanospray emitters. The graphite coated nanospray emitters still produced a stable nanospray signal despite the presence of a passivated surface. The polymer (i.e. polyaniline) coated nanospray emitters showed very low electrochemical activity and could not be thoroughly tested by CA. The relative short lifetimes seen in the electrochemical tests are qualitatively comparable with those obtained in nanospray experiments, in which only the outmost tip of the emitter is electrochemically active. However, the electrochemical stress during CA far exceeds the stress during ESI, which implies that CA can be used to perform quick and simple estimates of emitter stabilities. To our knowledge, this is the first time the electrochemical behavior of metal, polymer and graphite coated nanospray emitters has been compared.     

Aqueous Electrochemistry of Anthraquinone and Its Correlation with the Dissolved States of a Cationic Surfactant

Cyclic voltammetry was employed to study the electrochemical behavior of anthraquinone (AQ) in aqueous solution at a glassy carbon electrode using the sodium salt of anthraquinone-2-sulphonic acid (AQS). The cyclic voltammograms show a reduction wave and a corresponding oxidation wave. The electrochemical reaction of AQ in aqueous solution involves a two electron transfer process followed by a coupled chemical reaction and exhibits strong pH dependence at low pH (<4). A satellite peak is also observed at the cathodic side of the reduction wave for the reduction of the sulfonate group of AQS. The electrochemical investigation was also carried out in the presence of a cationic surfactant, cetyltrimethylammonium bromide (CTAB). Similar redox behavior can be observed for the electrochemical reaction of AQS in the presence of CTAB solutions similar to the aqueous media. The electrochemical responses have been found to depend on the dissolved states of the surfactant. The current-potential behavior of AQS depends on the concentration of CTAB and micellization has a profound effect on the electrochemical behavior of AQ.     

Application of Nanoparticles in Electrochemical Sensors and Biosensors

The unique chemical and physical properties of nanoparticles make them extremely suitable for designing new and improved sensing devices, especially electrochemical sensors and biosensors. Many kinds of nanoparticles, such as metal, oxide and semiconductor nanoparticles have been used for constructing electrochemical sensors and biosensors, and these nanoparticles play different roles in different sensing systems. The important functions provided by nanoparticles include the immobilization of biomolecules, the catalysis of electrochemical reactions, the enhancement of electron transfer between electrode surfaces and proteins, labeling of biomolecules and even acting as reactant. This minireview addresses recent advances in nanoparticle‐based electrochemical sensors and biosensors, and summarizes the main functions of nanoparticles in these sensor systems.     

Understanding the effects of diffusion coefficient and exchange current density on the electrochemical model of lithium-ion batteries

The diffusion coefficient and exchange current density are the two dominant parameters that determine the electrochemical characteristics of the electrochemical battery model. Nevertheless, both parameter values are generally adopted from well-known literature or experimental data measured under limited conditions and are sometimes overfitted to match actual electrochemical behaviors without full consideration. Herein, the diffusion coefficients and exchange current densities of a LiNi_0·4Mn_0·3Co_0·3O₂/Li cell are measured and applied to the electrochemical model (based on Newman's model) using four different electrochemical methods: galvanostatic intermittent titration technique (GITT), potentiostatic intermittent titration technique (PITT), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). Without any fitting, the model adopting the diffusion coefficient and exchange current density measured from PITT and EIS, respectively, simulates the actual voltage–capacity profiles well. Thus, this case study provides a valuable opportunity to understand the advantages and disadvantages of each measurement method in obtaining key experimental parameters for electrochemical battery models.     

Photometric and electrochemical detection of purine and pyrimidine compounds in reversed-phase and ion-exchange high-pressure liquid chromatography

An investigation of the optimal conditions for the determination of selected purine and pyrimidine compounds has been made by studying the separation efficiency of reversed-phase columns and ion-exchange columns and comparing the sensitivity of photometric and electrochemical detectors. The combination of ion-exchange HPLC with electrochemical detection proved very good for the separation of electroactive compounds, under the experimental conditions studied. Both types of column allow detection at the picomole level. In general the electrochemical detector appears to be the more sensitive of the two types.