Analytical Chemistry Commons^™

Study On The Microband Array Electrode-Based Glucose Microsensor, Neng-Qin Jia, Chui-Jue Sun, Lin Gao, Zong-Rang Zhang, Jian-Zhong Zhu, Guo-Xiong Zhang

Journal of Electrochemistry

The microband array electrode (MAE) consisting of 11 Pt microband of 5 m in wide, 2000 m long and 85 m gap was fabricated with a thin film techology. The MAE was characterized by means of cyclic voltammetry in a solution of K₃Fe(CN)₆ and H₂O₂. The results showed higher current density on MAE than on conventional Pt eletrode due to the strong edge effect of the former. A glucose microsensor was constructed with the substrate electrode of microband array. Microband array electrode was modified by Nafion followed by the immobilization of ferrocene onto …

In Situ Ftir Spectroelectrochemical Study Of Palladium Hexacyanoferrate Thin Film Deposited On Glassy Carbon Electrode, Ai-Li Bo, Xiang-Qin Lin

Journal of Electrochemistry

The electrochemically deposited Palladium hexacyanoferrate thin film on Glassy Carbon electrode (PdHCF|GC) has been studied in HCl, KCl and NaCl solutions by in-situ external reflection FTIR spectroelectrochemical technique. It is found that the behavior of the electroactive PdHCF film can be understood in terms of two states: Pd₂Fe(II)(CN)₆ formed in the inner layer and (M⁺)2Fe(II)(CN)₆ (M⁺: electrolyte cation) formed in the outer layer. The inner layer is oxidized at E_m=0.87 V in 1 mol/L KCl, while for the outer layer Em=0.77 V(vs. Ag/AgCl). In 1 mol/L NaCl or HCl solutions, …

Study Of The Effect Of Rare Earth Ions On Dna Using Cyclic Voltammetry And Spectroscopy, Hei-Bai Shen, Yu-Zhuan Kang, Hai-Feng Yang, Lin Yu, Zong-Rang Zhang

Journal of Electrochemistry

The interaction between rare earth ions(e.g. Eu³⁺ ,Ce³⁺, Er³⁺, Sm³⁺, Tb³⁺, La³⁺ and Nd³⁺) and DNA had been investigated by using Cyclic Voltammetry, Ultraviolet and Raman Spectroscopy. After the adding of Ce³⁺ ion to DNA solution, the cathodic peak current of Ce³⁺ ion reduction was found to decrease obviously, and the anodic peak current to decrease even more significantly. Differential UV spectra of Ce³⁺ ion depicted hyperchromic effect after the reaction of these two species and a new peak of 272 nm was found. Differential …

Direct Electro-Oxidation Synthesis Of D-Arabinose On Spectroscopic Graphite Electrode, Hei Wei, Huang Ying

Journal of Electrochemistry

D Arabinose synthesized by direct electro-oxidative decarboxylation of D gluconate on graphite electrode from aqueous solutions. The effects of D gluconate concentration, electrolysis potential, temperature and electrolyte composition on the current efficiency and product yield of electrosynthsis are discussed. The laboratory scale electrosynthesis was achieved with flow through cell. The optimum technology conditions for electrosynthesis were obtained with orthogonal design method. Both galvanostatic and potentionstatic conditions have been exploited, the later was found to be more effective.

In-Situ Raman Spectroscopic Study Of The Oxidation And Reduction Of Ag Electrode In Na2So4, Yan-Xia Chen, Kai-Qi Huang, Zhong-Qun Tian

Journal of Electrochemistry

In-situ Raman spectroscopy combined with cyclic voltammogram measurements was used to investigate formation of oxygen species at Ag electrode surfaces during the oxidation and reduction process in 0.1 mol/L Na₂SO₄ solution. The time dependent Raman spectra show that at potentials positive of 0.2 V, adsorption of oxygen atom occurs, while at the potentials positive of 0.4 V, some oxygen atoms migrate into subsurface of the Ag electrode and the other form strongly bound oxygen on the surface through chemical bond. At the same potentials, part of the silver atoms are oxidized and form Ag₂SO_{4 …}

Spectroscopic Investigation Of Ion Transport Mechanisms In Polyacrylonitrile Based Electrolytes, Zhaoxiang Wang, Biying Huang, Rongjian Xue, Xuejie Huang, Liquan Chen

Journal of Electrochemistry

Raman, IR, X-ray photoelectron (XPS), and NMR spectra of components in polyacrylonitrile based electrolytes have been studied. It is found that there are strong interactions among the components though different systems show different interaction characteristics. A concept of competition is proposed between the polymer matrix and the plasticizer on associating with the Li⁺ ions. By analyzing the important functions of the plasticizer, a possible mechanism of the ions transport in the polymer electrolyte is suggested.

Investigation On The Ellipsometry For The Detection Of Nickel Through Anodic Stripping Voltammetry, Wei Zhu, Yu-Ru Yang, Zong-Qing Huang

Journal of Electrochemistry

The ellipsometry with a new parameter Vop and anodic stripping voltammetry are used to analyze the nickel ions solutions with different concentration of 10^-6～10^-9 mol/L. It is shown that the results given by both methods are identical and the sensitivity and accuracy of ellipsometry are higher than anodic stripping voltammety.

The Electrode Process Of Some Organic Dyes Studied By Spectroelectrochemical Technique In Situ, Yinxuan Tang, Hangsheng Yang, Baoen Shen

Journal of Electrochemistry

Spectroelectrochemistry especially with in situ measurement in a cell provides a very useful mthodology for measuring the parameters of electrode process. In this paper, we report the determination of formal potentials, the number of electron transfer, the diffusion coefficient, the heterogeneous electron transfer rate constant and the transfer coefficient of some organic dyes (Methyelene blue, Neutral red, Indigo carmine) using spectroelectro chemical technique in situ.

Effects Of Tunneling Electrons And Local Field On Nanometer Region Solid / Liquid Interfacial Reactions ——Potential Controlled Stm Induced Nanoscale Modification Of H Terminated Si(111) Surfaces, Zhaoxiong Xie, Xiongwei Cai, Caihui Shi, Bingwei Mao, Zhaowu Tian

Journal of Electrochemistry

H-terminated n-Si(111) surface was found to be etched in 0.5% HF solution in nanometer scale while scanning the STM tip when the substrate potential was somehow lower than the open circuit potential at tunneling condition of V_b=+1.0 V (tip positive), I_t=1 nA. Much more stable Si surface was achievable at potentials much more negative than the open circuit potential (such as 500 mV negative to OCP) under the same tunneling condition. Furthermore, the etching rete at less negative potential was found to be somehow related to the tunneling current. These results indicate that the STM induced …

Determination Of Asphaltenes In Petroleum Crude Oils By Fourier Transform Infrared Spectroscopy, Brian K. Wilt

Theses, Dissertations and Capstones

An analytical method was developed to quantitatively determine the asphaltene content in petroleum crude oils by Fourier transform infrared spectroscopy (FT-IR). Asphaltenes are a solubility class of compounds found in crude oils. They are black to dark brown solids defined by their insolubility in n-alkane solvents. The structure of asphaltene molecules is polynuclear aromatic rings with alkyl side chains and heteroatoms, such as nitrogen, oxygen, and sulfur attached. Asphaltenes are known to cause oil well plugging and irreversible catalyst deactivation in refineries. The asphaltene content of 50 crude oils from a wide array of geochemical conditions was determined by the …

A Review Of Differential Electrochemical Mass Spectroscopy Techniqueⅰ. The Principle And Development Of Dems, Fujikawa Keikichi, Li Feng

Journal of Electrochemistry

No abstract provided.

Time-Resolved Electron Spin Resonance Spectroscopy For In-Situ Studies Of Electrochemical Systems, Lin Zhuang, Juntao Lu

Journal of Electrochemistry

No abstract provided.

Surface Raman Spectra Obtained From Various Electrodeposited Transidon Metals, Jingsong Gao, Bin Ren, Qunjian Huang, Zhongqun Tian

Journal of Electrochemistry

Good quality potential-dependent surface Raman spectra of pyridine were obtained for the first time from a series of transition metals, e. g., Fe, Co, Ni, Ru, Rh, Pd and Pt, which were electrodeposited on non-SERS-active substrates. The influences of the applied potential and the nature of metal on the adsorption behaviors were discussed briefly. This result illustrates that Raman spectroscopy is becoming a more general and powerful tool to study various electrochemical interfaces.

In Situ Studies Of Copper Electrodepostion On Hopg By Using Ecstm, Zhaoxiong Xie, Bingwei Mao, Xiangdong Zhuo, Jiqian Mu, Zhaowu Tian

Journal of Electrochemistry

In this paper, copper electrodepostion on HOPG had been in situ studied by using a homebuilt electrochemical scanning tunneling microscopy (ECSTM). Three dimensional nucleation and subsequent growth of copper crystals were found as the initial stage of copper deposition on HOPG. In the case of lower overpotential or lower concentration of Cu²⁺ , the bulk deposited copper layer tended to form smooth terraces, and grow at the edge of steps. The terraces were stable to some extent, which made it possible to be observed with atomic resolution. At a higher overpotential, the crystal size of copper were somehow smaller. …

Statistical Mechanical Treatment For The Electrical Double Layer At Ities: Analysis Of Mvn Model, Jintian Wu, Shengpei Chen, Hui Wang, Wenduan Su

Journal of Electrochemistry

A statistical mechanical treatment for electrical double layer at the interface between two immiscible elecrolyte solution (ITIES) is presented by using grand canonical method based on the MVN model.

For the MVN model, the ITIES was represented by that the two space charge regions are separated by an inner layer of the oriented solvent molecules. Assuming that the ions were allowed to penetrated into the solvent compact layer over some distance, then the grand canonical partition function of the inner layer at ITIES can be given. While the mean field approximation is employed to estimate the interactive potential energy of …

The Applications Of Poap Ni2+ Films Modified Electrode As Sensor For Alcohol, Bingzeng Hua, Wenyun Hu, Yanzhen Chen

Journal of Electrochemistry

POAP Ni²⁺ films modified electrode can electrocatalyzes significantly the oxidation of alcohol. The modified electrode can be used as the electrochemical sensor for the detection of alcohol. But the oxidation of alcohol is effected by the thickness of films、the concentration of nickel ion in films, pH of electrolyte, as well as temperative. All of those conditions have been studied in order to achieve stable response current during the oxidation of alcohol, and the relation between concentration and current has been made. At last the major characteristic parameters, such as the low limitation of concentration, the response time, the ability …

Surface Raman Spectra Of Pyridine And 2 Mercaptopyrimidine Adsorbed On Rough Nickel Electrode, Qunjian Huang, Jinsong Gao, Xiongwei Cai, Bingwei Mao, Mingsen Zheng, Zhongqun Tian

Journal of Electrochemistry

The Raman spectra of pyridine and 2-mercaptopyrimidine (2-MP) adsorbed on bare nickel electrodes roughened by a HNO₃ etching procedure have been obtained for the first time by utilizing a highly sensitive confocal Raman microscope. Their adsorption behaviours are discussed briefly. This primary result illustrates a great potential for in-situ Raman spectroscopy in the study of chemical and electrochemical processes of transition metal surfaces.

Study Of Electrochemical Behaviour Of Myoglobin Using Cyclic Voltammetry And Synchronous Fluorescence Spectroscopy, Ju Chou, Haihong Zhou, Tianhong Lu, Yue Wu

Journal of Electrochemistry

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Application Of Electroanalytical Chemistry In Heteropoly Compounds System──Studies On The Redox Properties Of Bis(Undecatungstometalate) Lanthanates, Weiqing Wang, Xiumei Zhang, Jingfu Liu

Journal of Electrochemistry

The redox properties of Ln(MW₁₁)₂ (M=As, Ti, Ga; Ln=La, Ce, Pr,Nd, Sm, Eu, Gd, Dy) are systematically studied. It has been found that the redox order is La(AsW₁₁)₂ > La(TiW₁₁)₂ >La(GaW₁₁)₂.The reduction process of Ln(MW₁₁)₂ anion has been discussed.

Simultaneous Detection System Combining Studies Of Programmedpotential Step Technique And Time-Resolved Ftir Spectroscopy, Shigang Sun, Xiaoyu Chen, Guoqiang Lu, Wenfeng Lin, Nanhai Li, Shenpei Chen, Hongping Dai, Jiqian Mu

Journal of Electrochemistry

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Studies Of In-Situ Raman Spectroscopy On Deprotonation And Degeneration Of Ppy Films, Jinsong Gao, Jing Chen, Yanzhen Chen, Qi Xue, Zhongqun Tian

Journal of Electrochemistry

By combining the in-situ Raman spectroscopic technique with the normal electrochemical measurements, the behavior and structure of PPY films in neutral or basic solutions were studied. The oxidized PPY loses protons on the N atoms of pyrrole rings and is deprotonated in these solutions, resulting the formation of the quinoid structure. It makes the C=C stretching vibration bonds of PPY split. Because this quinoid structure can′t be further oxidized, the PPY becomes more difficult to be oxidized and less reversible with the increasing of pH value of solutions and the degree of deprotonation of PPY. In the strong basic solution …

A Sutface-Enhanced Raman Spectroscopic Study On The Inhibition Mechanism Of Bmat On Stainless Steel In Hydrochloric Acid Solutions, Yinghua Zha, Baoming Wei, Zhongqun Tian, Changjian Lin

Journal of Electrochemistry

The absorbtion of some nitrogen and sulfur compounds such as BMAT on 18-8stainless steel (SS) in 0.5% HCl were investigated by surface enhanced Raman scattering (SERS) spectroscopy. The SERS spectra of BMAT adsorbed on SS were measured using a SS electro deposited with discontinuous silvet micro-islands. The results show that the inhibitor, BMAT, is chemisorbed on the SS surface through the N atom. Under the influence of π-electron interaction, BMAT can be adsorbed on SS surface at an angle. The allyls in BMAT molecules play the role of steric hindrance in the inhibition effect.

Study Of Electrochemical Properties Of Ni(Oh)2/Niooh With Spectroscopic Ellipsometry, Shengtao Zhang, Zongqing Huang

Journal of Electrochemistry

Electrochemical reactions of Ni(OH)₂ /NiOOH system were studied by using in-situ spectroscopic ellipsometry and the conventional electrochemical metheds. By fitting data from ellipsometric measurements, a transformation medel of the surface film was obtained for cathedic and anodic processes. The results indicated that the transformation medel after cobalt implantation almost remained the same as that before cobalt implantation, but the electrochemical properties were affected obviously by implantation of cobalt.

Application Of Voltammetry In Analysis Of Electroplating Baths, Jiayuan Xu, Shaomin Zhou

Journal of Electrochemistry

Based upon the electrochemical characteristics of the components or impurities tobe determined in the electroplating baths, and the inhibition or activation effect of the additives used on the electrodepcosition processes of metals and alloys, direct voltammetry, indirect voltammetry andvoltammetry with anodic stripping of metallic deposits, were suggested to determine the concentrationof some components, several impurities and the additives usually used in the electroplating baths. The procedure of those methtods are simple and rapid ,and are suitable to be used for in-situ control in electroplating workshops.

Initiation And Study Of Localized Corrosion By Scanning Electrochemical Microscopy, David O. Wipf

CAS Publications

This paper describes methods to study the initiation and formation of localized corrosion pits on stainless–steel and aluminum samples. These methods are based on the use of a scanned probe microscope, the scanning electrochemical microscope (SECM). The SECM is specifically designed for operation in electrolyte solution and so is uniquely suited for examination of corrosion processes. SECM imaging of a corrosion pit on stainless steel is presented. In addition, the initiation of single pits on aluminum and stainless steel by using the SECM tip to electrogenerate a local source of Cl^– is described.

The Use Of Thermal Analysis In The Identification And Characterization Of Fibers Of Forensic Interest, Ronald J. Coffey

All-Inclusive List of Electronic Theses and Dissertations

This study investigates the use of thermal analysis for the identification and characterization of fibers for forensic purposes. Fibers such as polyesters, polyacrylics, polypropylenes and nylon were investigated by Differential Thermal Analysis (D.T.A.) and Thermogravimetric Analysis (T.G.A.) to see if their resulting thermograms were characteristic of each fiber. Also, infrared analysis was performed on each fiber. In addition, such factors as heating rate and sample size along with fiber blends were studied as to their effect on thermograms. As a result of this study several important conclusions may be drawn. Although it was found that for the most part D.T.A. …

A Study Of Resins From Carbohydrates, Edward F. Sullivan

Bachelors’ Theses

The availability of large amounts of carbohydrates, and the need in the past years of larger markets for the available supplies of sugar have lead a number of sugar companies to investigate the possibilities of synthetic resins from carbohydrates. Although in the last ten or twelve years, a number of steps have been taken in the investigation of sugar resins, the information available has been restricted to a few patents. Consequently, information on the chemistry of the problem has been neglected. Thus, this work, for the most part, covers partially the possibilities of producing alkyd resins from saccharides, as well …

A Method For Comparing And Measuring The Drying Time Of Glues, William C. Strutz

Bachelors’ Theses

The measurements or quality in glue testing are arbitrary and are of value only when compared to a standard glue or when comparing one glue to another. Glues have been used for hundreds of years, but it has been only in the last forty or fifty years that any scientific investigations of any consequence have been made. Prior to this time glues were made by rule of thumb by practical men who learned the art of glue making from other practical men in the business and by contact with the industry. "When the United States entered the Great War and …

Wax Analysis With Special Reference To Montan, Spermaceti, And Chinese Insect Wax, Margaret M. Plonsker, Margaret E. Seippel

Bachelors’ Theses

The presentation of this thesis under joint authorship finds its justification in the fact that much of the experimental work, though performed individually, is of such a nature as to warrant a unified description. In this way the reader is afforded a better representation and clearer conception of the problem, and a substantial guide for further investigation. Though much work has been done in the field of wax analysis, little is known of the higher fatty acids and alcohols of many of the waxes. Their isolation has been infrequent, and few if any of their derivatives have been formed. It …

Hardness And Porosity In Chromium Plating, Waldemar Wick

Bachelors’ Theses

In recent years chromium plating has been subjected to much research due to its ever-increasing demand. The results of these investigations have demonstrated the valuable properties of this plate. Of its many advantageous properties, hardness is one of the outstanding ones, but its application in industry is as yet not fully realized. This being due to the fact that it is difficult to produce a plate that is uniform and does not chip. Many chemists have investigated the porosity of the chromium plate in order to produce a coating that could be used for protective purposes, but there seems to …