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.     

Electrocatalytic oxidation of the antiviral drug acyclovir on a copper nanoparticles-modified carbon paste electrode

The electrocatalytic oxidation of acyclovir (Zovirax) on two different copper-based electrodes: copper microparticles- and copper nanoparticles-modified carbon paste electrodes (denoted as micro-CPE and nano-CPE, respectively) was voltammetrically investigated. In the voltammogram recorded using micro-CPE, a single anodic oxidation peak appeared, while nano-CPE resulted in two overlapped anodic peaks. The anodic currents were related to the electrocatalytic oxidation of acyclovir via the electrogenerated active species of Cu(III) with an EC’ mechanism. Acyclovir was oxidized with higher rates at low potentials on nano-CPE compared to micro-CPE. This was related to the nanosize effect of copper nanoparticles. The constants of the electrocatalytic oxidation process and the diffusion coefficient of acyclovir were reported. A sensitive and time-saving determination procedure was developed for the analysis of acyclovir and the corresponding analytical parameters were reported. The proposed amperometric method was applied to the analysis of commercial pharmaceutical products (tablets and topical cream) and the results were in good agreement with the declared values.     

Anodic transformation of cycloheptatriene to tropone and tropolone

Cycloheptatriene (CHT) has been directly transformed to 7-methoxycycloheptatriene (7-MCHT), an equivalent compound to a tropylium salt, by the anodic oxidation of CHT in methanol. The further anodic oxidation of 3-MCHT prepared from 7-MCHT has been found to be an effective method of synthesis of tropone and tropolone.     

Pd-Mn/Stainless Steel Wire Mesh Catalyst for Catalytic Oxidation of Toluene,Acetone and Ethyl Acetate

A new 0.1%Pd‐6%Mn/stainless steel wire mesh catalyst was prepared and used for volatile organic compounds (VOC) elimination. The supported palladium and manganese catalyst over the stainless steel wire mesh was prepared by using an impregnation method. When an anodic oxidation technology was employed, an anodic oxidation membrane appeared on the stainless steel wire mesh. On the 0.1%Pd‐6%Mn/stainless steel wire mesh catalyst calcined at 500°C, the total oxidation of toluene, acetone and ethyl acetate was respectively at 260, 220 and 320°C. The activity could be stable for over 700 h for toluene oxidation. The scanning electron microscopy (SEM) investigation of the Pd‐Mn/stainless steel wire mesh catalyst shows that the presence of anodic oxidation membrane on the support surface is important for better dispersion of active phases.     

Generation of alkoxycarbenium ion pools from thioacetals and applications to glycosylation chemistry

[reaction: see text] Alkoxycarbenium ions have been generated and accumulated as "cation pools" by the low-temperature electrochemical oxidation of alpha-phenylthioethers. Although an unsuccessful attempt to accumulate glycosyl cations was made, a one-pot method for electrochemical glycosylation, which involves anodic oxidation of thioglycosides to generate glycosyl cation equivalents followed by their reactions with glycosyl acceptors, has been developed.     

Application of anodic dissolution method for a study of electrocolored aluminum oxides

The anodic dissolution of color carrier of colored aluminum anodic oxide films (AOF) is studied before and after their coloring, using ac in various electrolytes containing Cu(II). The voltammetric polarization curves of anodic dissolution of colored AOF in 0.1 M H₂SO₄ depend on the amount of copper deposited in the pores and its oxidation state (Cu, Cu₂O, CuO). Analytical and X-ray diffraction examination of AOF prior to and after the anodic dissolution shows that the anodic dissolution method is inapplicable for the determination of the oxidation state of copper electrodeposited in AOF pores or the amount of copper oxides.     

The Influence of the Capping Agent on the Oxidation of Silver Nanoparticles: Nano‐impacts versus Stripping Voltammetry

The influence of capping agents on the oxidation of silver nanoparticles was studied by using the electrochemical techniques of anodic stripping voltammetry and anodic particle coulometry (“nano‐impacts”). Five spherical silver nanoparticles each with a different capping agent (branched polyethylenimine (BPEI), citrate, lipoic acid, polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP)) were used to perform comparative experiments. In all cases, regardless of the capping agent, complete oxidation of the single nanoparticles was seen in anodic particle coulometry. The successful quantitative detection of the silver nanoparticle size displays the potential application of anodic particle coulometry for nanoparticle characterisation. In contrast, for anodic stripping voltammetry using nanoparticles drop casting, it was observed that the capping agent has a very significant effect on the extent of silver oxidation. All five samples gave a low oxidative charge corresponding to partial oxidation. It is concluded that the use of anodic stripping voltammetry to quantify nanoparticles is unreliable, and this is attributed to nanoparticle aggregation.     

Anodic oxidation of organic compounds based on the cation exchange reaction between KBF4 and solid-supported acids

We have developed a novel electrolytic system for anodic oxidation of organic compounds based on the cation exchange reaction between potassium tetrafluoroborate (KBF₄) and solid-supported acids. It was clarified by cyclic voltammetry as well as preparative electrolyses that hydrogen tetrafluoroborate (HBF₄) derived from the cation exchange reaction acts as a supporting electrolyte in MeCN. On the basis of the electrolytic system, anodic oxidation of 1,2,4-trimethoxybenzene was carried out to provide the corresponding homocoupling product in quantitative yield. Furthermore, anodic oxidation of benzyl alcohols having not only electron-donating but also electron-withdrawing groups at the para position was successfully achieved by optimizing the reaction conditions.     

Untersuchungen zur atomspektroskopischen spurenanalyse in AIIIBV-halbleiter-mikroproben—III: Untersuchungen zur schichtabtrennung und zur spurenanalyse in dünnen GaAs schichten

Three methods for stripping thin layers of GaAs have been compared with regard to depth of layer and reproducibility. They are (1) chemical etching with methanolic bromine solution, (2) mechanical separation with a microtome, (3) chemical etching after a preliminary amperostatic anodic oxidation. Conditions were optimized. The depth of strip was 0.4 μm for chemical etching, 1 μm for the mechanical separation and 0.02 μm for the anodic oxidation method. Thus the anodic oxidation is specially suitable for profile analysis, and the mechanical method for investigation of thicker layers; chemical etching lies between them. The trace elements in the micro samples thus obtained were determined by d.c. are atomic-emission spectrography (AES) and atomic-absorption spectrometry with electrothermal atomization in a graphite tube (AAS). The absolute and relative detection limits of AAS for the 0.1–0.2 mg micro samples were on average better by an order of magnitude than those of AES. The advantage of AES lies in the possibility of simultaneous determination of several elements. in der Möglichkeit der Simultanbestimmung mehrerer Elemente.     

Determination of Reactive Intermediates During Anodic Oxygen-transfer Reactions at Lead Dioxide

IntroductionSincethepastdecade ,electrochemicalmethodsforelectrosynthesis ,wastewatertreatmentandorgan iccompounddeterminationhavebeenwidelydevel oped[1— 6 ] .Thebasicprincipleisthatorganicsub stancesareelectrochemicallyoxidizedintothedesiredproducts.However ,inmanycasesthedirectoxida tionoforganicspeciesinanaqueoussolutionatasim plemetaloracarbonelectrodeisnotpossiblebecausethehighpotentialsrequiredfortheoxidationoforgan iccompoundsusuallyresultinoxygenevolution .Therefore ,theproperchoiceof…     

Paired Electrochemical Reactions and the On‐Site Generation of a Chemical Reagent

While the majority of reported paired electrochemical reactions involve carefully matched cathodic and anodic reactions, the precise matching of half reactions in an electrolysis cell is not generally necessary. During a constant current electrolysis almost any oxidation and reduction reaction can be paired, and in the presented work we capitalize on this observation by examining the coupling of anodic oxidation reactions with the production of hydrogen gas for use as a reagent in remote, Pd‐catalyzed hydrogenation and hydrogenolysis reactions. To this end, an alcohol oxidation, an oxidative condensation, intramolecular anodic olefin coupling reactions, an amide oxidation, and a mediated oxidation were all shown to be compatible with the generation and use of hydrogen gas at the cathode. This pairing of an electrolysis reaction with the production of a chemical reagent or substrate has the potential to greatly expand the use of more energy efficient paired electrochemical reactions.     

阳极氧化法制备TiO2多孔薄膜

本文综述了制备TiO2薄膜的各种方法,详细介绍了阳极氧化法制备TiO2多孔膜的进展,在非含氟电解液体系中,对纯钛进行阳极氧化处理可制得表面呈无规则生长的多孔膜结构;在含氟电解液体系中,则可自组织形成高度有序的TiO2纳米管阵列,并指出阳极氧化法是可在常温低压下进行、操作工艺简单、薄膜性能稳定、再现性好的一种最具工业化应用潜力的制备方法。     

Oxidation of L-cysteine at a fluorosurfactant-modified gold electrode: lower overpotential and higher selectivity

We describe the oxidation of L-cysteine (CySH) at a fluorosurfactant (i.e., Zonyl FSO)-modified gold electrode (FSO-Au). Significantly reduced anodic overpotential of CySH was observed. The FSO layer inhibited the adsorption of CySH and its oxidation products at the gold electrode surface, and the low coverage of the adsorbed thiol-containing species might account for the more facile electron-transfer kinetics of free CySH at low potentials. An electrochemical impedance spectroscopy study revealed the lower charge-transfer resistance of CySH oxidation at the FSO-Au electrode as compared to that at a bare gold electrode. Interestingly, although the FSO layer facilitated CySH oxidation, the anodic responses of other electroactive biological species such as glucose, uric acid, and ascorbic acid were generally suppressed. Furthermore, the modified electrode was capable of differentiating CySH from other low-molecular-mass biothiols such as homocysteine and glutathione. The unique features of the FSO-Au electrode allowed for the development of a highly selective method of detecting CySH in complex biological matrices. The direct determination of free reduced and total CySH in human urine samples has been successfully carried out without the assistance of any separation techniques.     

二次阳极氧化方法制备有序多孔氧化铝膜

通过二次阳极氧化方法制备多孔氧化铝膜与一次阳极氧化方法制备多孔氧化铝膜孔排布规律性的对比,结果发现,二次阳极氧化方法制取的多孔氧化铝膜孔排布规律性明显好于一次阳极氧化法制取的多孔膜.在几个微米范围内,孔呈理想的六角排布.去除一次阳极氧化膜后,二次阳极氧化得以在更良好的表面进行,制取的氧化铝膜孔规律性和有序度更高.有序区域的尺寸与晶粒内的亚晶大小有一定关系.     

阳极氧化法制备TiO2多孔薄膜

本文综述了制备TiO₂薄膜的各种方法,详细介绍了阳极氧化法制备TiO₂多孔膜的进展,在非含氟电解液体系中,对纯钛进行阳极氧化处理可制得表面呈无规则生长的多孔膜结构;在含氟电解液体系中,则可自组织形成高度有序的TiO₂纳米管阵列,并指出阳极氧化法是可在常温低压下进行、操作工艺简单、薄膜性能稳定、再现性好的一种最具工业化应用潜力的制备方法。     

Cu/PAA复合膜的偏振特性

应用扩孔和增大阳极氧化电压的方法制备了不同孔径的多孔铝模板,并以交流电沉积法在该模板沉积铜纳米线.测量了铜/多孔铝复合膜的透射光谱和偏振光谱.实验表明,扩孔和增加阳极氧化电压都使样品的透射率下降,但扩孔不能提高它的偏振性能;提高模板氧化电压则可以提高样品的消光比,且消光比随纳米线直径的增加而增加.     

Controlled Directional Water‐Droplet Spreading on a High‐Adhesion Surface

Controlled directional spreading of a droplet on a smart high‐adhesion surface was made possible by simply controlling anodic oxidation. The wettability gradient of the surface was controlled from 0.14 to 3.38° mm^?1 by adjusting the anodic oxidation conditions. When a water droplet made contact with the substrate, the droplet immediately spread in the direction of the wettability gradient but did not move in other directions, such as those perpendicular to the gradient direction, even when the surface was turned upside down. The spreading behavior was mainly controlled by the wettability gradient. Surfaces with a V‐ or inverse‐V‐shaped wettability gradient were also formed by the same method, and two droplets on these surfaces spread either toward or away from one another as designed. This method could be used to oxidize many conductive substrates (e.g., copper, aluminum) to form surfaces with variously shaped wettability gradients. It has potential for application in microfluidic devices.     

石墨电极上硫化钠的阳极氧化机理探索

电解硫化氢气体的碱性吸收液（Ｎａ２Ｓ表示）产生单质硫和氢气的研究是治理硫化氢废气的一种新方法［１ -７］,较之Ｃｌａｕｓ法有许多优点［３,４］,这对环境保护和资源回收均具有重要的实际意义．文献对硫化物水溶液电化学氧化机理的研究主要着重于在某些贵金属阳极上,包括某些硫化矿的湿法冶金反应过程的研究［８,９］,光电化学电池中使用多硫化物的研究［１０ -１３］,以及硫化物电解时产生单质硫的电催化活性研究［１４］等 ;但在石墨阳极上硫化物电化学氧化机理的研究报导却很少［３,４］．本文研究在石墨阳极上硫化钠水溶液…     

Anodic oxidation of organic pollutants: Anode fabrication,process hybrid and environmental applications

This review summarizes the recent progress in anodic oxidation of organic pollutant for water and wastewater treatment. It supplies the advances in anodes fabrication to improve the anodic performance by different modifications and preparation strategies, focusing on non-active anodes including boron-doped diamond (BDD), PbO₂, SnO₂ and Ti-based anode (e.g., Ti₄O₇, blue titanium oxide). Meanwhile, the tendency of anodic oxidation coupled or combined with other processes (adsorption, membrane separation, biological treatment and advanced oxidation process) for pretreatment or advanced treatment of organic pollutant is presented. Finally, anodic oxidation for environmental application is briefly described; several challenges need to be overcome and perspectives for future study are critically proposed.     

Electrochemical treatment of wastewaters containing organic pollutants on boron-doped diamond electrodes: Prediction of specific energy consumption and required electrode area

A theoretical analysis is presented for the prediction of the specific energy consumption and the required electrode surface for the electrochemical combustion of organic compounds on synthetic boron-doped diamond (BDD) thin film electrodes. The model is formulated for a perfect mixed electrochemical reactor operated as a batch recirculation system under galvanostatic conditions. The anodic oxidation of organics is assumed to be under diffusion control. An experimental validation with the anodic oxidation of phenol and under different experimental conditions is also provided.