Chemistry Commons^™

Effect Of Temperature On Retention Of Enantiomers Of Β-Methyl Amino Acids On A Teicoplanin Chiral Stationary Phase, Antal Péter, Gabriella Török, Daniel W. Armstrong, Géza Tóth, Dirk Tourwé

Chemistry Faculty Research & Creative Works

The isocratic retention of enantiomers of β-methyl amino acids (β-methyltyrosine, β-methylphenylalanine, β-methyltryptophan and β-methyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid) was studied on a teicoplanin-containing chiral stationary phase at different temperatures and at different mobile phase compositions, using the reversed-phase mode. With variation of both mobile phase composition and temperature, almost baseline separations could be achieved for all four enantiomers of sterically hindered amino acids. The retention factors and selectivity factors for the enantiomers of all investigated compounds decreased with increasing temperature. The natural logarithms of the retention factors (ln k) of the investigated compounds depended linearly on the inverse of temperature (1/T). van 't …

Capillary Zone Electrophoresis Studies Of Sulfur Containing Compounds, Francisco Rodriguez

Masters Theses & Specialist Projects

Up to this point in time, complex mixtures of tertiary sulfonium ions have been separated or analyzed employing conventional methods like HPLC or NMR procedures. In this thesis the researcher presents a new approach, the use of Capillary Zone Electrophoresis (CZE) for the analysis of these types of ions as well as the closely related thiophenium ions. CZE offers an unprecedented advantage in that separations can be employed for speciation or quantitation of complex mixtures by using the appropriate standards or specific detectors. For the study, model sulfonium and thiophenium ions were used to determine the feasibility of the separation …

Phorbol 12-Myristate 13-Acetate Stimulates Lysophosphatidic Acid Secretion From Ovarian And Cervical Cancer Cells But Not From Breast Or Leukemia Cells, Zhongzhou Shen, Jerome Belinson, Richard E. Morton, Yan Xu

Chemistry Faculty Publications

Lysophosphatidic acid (LPA) is present in ascites from patients with ovarian cancer. It stimulates calcium release and growth of ovarian cancer cells bothin vitroandin vivo.Recently, we found that LPA levels were significantly elevated in plasma from patients with ovarian cancer and other gynecological cancers. In contrast, LPA levels were not elevated in patients with breast cancer and leukemias. In view of this, we investigated whether gynecological cancer cells could produce LPA. LPA was extracted from the supernatant of cells culturedin vitroand purified by thin layer chromatography. After hydrolysis and transmethylation, the fatty acid derivatives were analyzed by gas chromatography. We …

Principal Component Mapping Applied To Raman Microspectroscopy Of Fiber-Reinforced Polymer Composites, C. M. Stellman, K. S. Booksh, A. R. Muroski, M. P. Nelson, Michael L. Myrick

Faculty Publications

We describe the development and implementation of a spectroscopic Raman imaging system using Principal Component data analysis. Raman microspectroscopy followed by multivariate data analysis and principal component mapping has been used to investigate the spatial variations of chemical and physical properties at interfaces in glass-reinforced composites on the micrometer scale. A protocol for monitoring chemical and physical variances via multivariate statistics has been developed and a preliminary study of a "real world" glass-reinforced composite is presented. It is demonstrated that multivariate Raman imaging is more precisely interpretable than traditional univariate methods and that by appropriately choosing distinct spectral regions (such …

Synthesis, Characterization And Photophysical Behavior Of A Cr(Iii) Bimetallic System, Yan Chen

Masters Theses

Many binuclear transition metal complexes have been studied to understand the nature of interactions between the metal centers. People have found Simultaneous Pair Excitation phenomenon in some bimetallic system that can serve as a potential source of Non-Linear Optical behavior.

Thus a series of Cr₂ -([14]aneN₄)₂-X₄ⁿ⁺ complexes were synthesized and characterized. Only the cis,cis configuration was found. The results were compared with those of their monomer analogs. The electronic structures are very similar in both monomer and dimer complexes. The quantum yield, UV-Vis absorption and lifetime studies suggested a possible coupling between the …

Nickel Subsulfide Can Protect Human Fibroblasts From The Mutagenic Effect Of Benzo[A]Pyrene Diolepoxide, Samir M. Hamdan

Masters Theses

Cancer researchers are interested in identifying the environmental causes and synergistic influences of different carcinogens. It is important to examine the combined effect of multiple carcinogens since this is a more realistic representation of the true environmental situation in which we are exposed daily. Our study has reported that pretreating human fibroblasts with nickel subsulfide followed by the simultaneous treatment with both nickel subsulfide and benzo[a]pyrene diolepoxide (BPDE) can protect human fibroblasts from the mutagenic effects of BPDE. These results correlate well with our previous chromium-BPDE co-treatment work, suggesting a transition metal dependent protective effect. This protective effect was dependent …

Development Of Chronoamperometric Logarithmic Signatures With Application To Drug-Package Interactions And Mechanism Elucidation, Beth Sarsfield

Seton Hall University Dissertations and Theses (ETDs)

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Investigation Of Peptide-Dna Interactions: Synthesis, Characterization And Applications Of Lysyl-Fluorophenylalaninamides, Teresita T. Ortega

Seton Hall University Dissertations and Theses (ETDs)

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Separation And Determination Of Monochlorophenols By Capillary Zones Electrophoresis, Zarina Yasmin Banu

Masters Theses

Chlorine has been widely used in industry. One of the most common uses of chlorine is in municipal water treatment plants. Chlorine reacts with a variety of organic compounds, among these are phenol and its derivatives which are commonly found in natural waters. When these compounds react with chlorine, a variety of chlorine substituted and oxidized products result depending on concentrations, pH, and temperature. In order to study these reactions it is necessary to separate and determine the various products produced.

Earlier studies have shown 3-chloro and 4-chlorophenol cannot be separated by commercial GLC columns. GC/MS (electron impact) measurements cannot …

The Effect Of Suspended Particles On The Corrosion Resistance Of Electrodeposited Zinc Powders, Qing-Wen Li, Qing Yang, Xi Xia

Journal of Electrochemistry

Zinc powders were electrodeposited from ZnCl₂ baths with containing suspension of unsoluble particles such as graphite, PbO₂, SnO₂, TiO₂, SiO₂ etc.. The structure, morphology and corrosion behavior of zinc powder were analyzed. SEM results showed that the dendritic growth of zinc can be inhibited by applying the suspension method. Suspension of PbO₂, SnO₂, TiO₂, SiO₂ and In₂O₃ could greatly improve the corrosion protection of zinc powder in 5 mol/L KOH. In addition, fractal theory is employed to further explain the results

Electrochemical Investigation Of Effect Of Br- On Redox Behavior Of (Tpp)Co, Chuan-Wei Yan, Hai-Chao Lin, Xiang-Qin Lin

Journal of Electrochemistry

The effect of Br^- anion on electrochemical behavior of (TPP)Co was investigated in 1,2 dichloroethane solution by microelectrode and thin layer cyclic voltammetry technique. It was found that the axially coordination of one Br^- anion to (TPP)Co(Ⅲ)(Br^-)₂ shifts the potential of porphyrin system to more positive value. The reduction peak of 0.12 V (vs.SCE) is attributed to the reduction of (TPP)Co(Ⅲ)(Br^-). It is also postulated that the reduction of (TPP)Co(Ⅲ)(Br^-)₂ occurred at a more negative potential where the reduction of the Co(Ⅱ)/Co(Ⅰ) process happened.

The Study On The Performance Of Mcfc Matrix Prepared By Flow Cast, Hua-Xin Lin, Bao-Lian Yi, Nai-Chao Li, Tian-Xi Qu, En-Jun Zhang, Lian-Yin Kong, Ying-Cai Chen

Journal of Electrochemistry

The matrix for MCFC were prepared by flow cast technique which gives reproducible and reliable results. Its mean pore radius is about 0.18 μm, and the porosity is about 65%. The performance of MCFC stacked with this type of matrix is 0.854 V at 200 mA/cm².

Oxygen Evolution Behavour On Ni Electrode In Koh Solution, Xiao-Yan Cao, Hua-Tang Yuan, Zuo-Xiang Zhou, Yun-Shi Zhang

Journal of Electrochemistry

The steady-state polarization curves of oxygen evolution were measured at temperatures between 22～70 ℃ on Ni electrode in 30 wt.% KOH solution by galvanostat methode. The exchange current densities, Tafel slopes and transfer coefficients were studied. It was found that 40 ℃ is a special temperature, near which the kinetic parameters change abrupdy. The Tafel slopes for oxygen evolution reactions at higher overpotentials change from more than 120 mV to about 70 mV when the temperature raises to 40～70 ℃ from 22～35 ℃. Simultaneously, the heat of activation is changes from 79.88 kJ/mol to 55.32 kJ/mol. Moreover, the -(η/Τ) i …

Study On Ni-Co-S-Mo Alloys New Cathode Material For Aquous Electrolysis, Yuan-Shou Xie, Quan-Feng Liu

Journal of Electrochemistry

The parameters of electrodeposion of Ni-Co-S-Mo alloy were studied. The experimental results indicate that the electrodeposition alloy shows high catalytic activity for hydrogen evolution reaction, as well as better mechanical strength and higher chemical stability. The mechanism of catalytic hydrogen evolution reaction on this type of alloy electrode was also investigated by means of polarization curve and cyclic voltametry.

Primary Research Of Reversible Proton Exchange Membrane Regenerative Fuel Cells, Zhi-Gang Shao, Bao-Lian Yi, Ming Han

Journal of Electrochemistry

In this paper, we report the results of our studies on regenerative proton exchange membrane fuel cell (RPEMRFC) catalysts, electrode preparation and their performances. The Pt catalyst for the oxygen electrode was replaced by 60 w%Pt + 40 w%IrO₂ which reduces polarization by 0.2 V in a polymer protone exchange membrane fuel cell. The cycle performance of RPEMRFC was found to be manly effected by the stability of the diffiusion layer of bifunctional oxygen electrode.

The Latest World Wide Progress In Solid Oxide Fuel Cell, Yi Jiang

Journal of Electrochemistry

Solid oxide fuel cell (SOFC) is a novel, green electricity generation technology, which has been showing rapid development since 1980's. In light of its high efficiency, environmental friendly, fuel adaptability and long term stability, the Research, Development and Demonstration (RD&D) of this hype of full cell have been emphasized in a large number of developed countries. Based on the information communicated at the latest symposium on SOFC held last year in Aachen (Germany) and the knowledge gained through years of research in this field, a comprehensive review on the latest development of the tubular, this planar SOFC as well as …

A Preliminary Study Of The Synthesis Of Tin-Based Amorphous Material And Its Behavior On Lithium Intercalation, Li Liu, Han-Xi Yang, Ju-Tang Sun, Xing-Ping Ai

Journal of Electrochemistry

An amorphous lithium inserting anode material based on Tin oxide glass was synthesized by salification in solution and its properties on lithium intercalation was investigated by X ray diffraction (XRD), microelectrode voltammetry and charge discharge measurements. The results have shown that this kind of material has considerable electrochemical reversibility toward lithium intercalation deintercalation. The available discharge capacity of the material reaches 430 mAh/g with charge-discharge efficiency over 90%, showing a great potential for practical use.

Corrosion Characteristics Of Electrodeposited Ni-Mo-P Alloy Immersed In Nacl Solution, Yue Zeng, Hong-Xin Huang, Xiao-Ming Xiao, Shi-Xun Lian, Su-Wei Yao, He-Tong Guo

Journal of Electrochemistry

The corrosion characteristics of electrodeposited Ni-Mo-P alloy immersed in 5wt.% NaCl solution were investigated using immersion, anodic polarization curves, XPS and AES analysis. The corrosion rates of amorphous Ni Mo P alloys are lower than that of crystalline Ni-Mo-P alloys. Anodic polarization curve experiments show that for the electrodeposited Ni-Mo-P alloys, the nickel mol fraction of which has in between 0.719 and 0.868, the corrosion potential moves to positive with the increase of P content, and the peak current value of active region increase with the increase of Mo content in alloys, though the effects of P content on the …

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.

Study On Electrosynthesis Of Butyl Butyrate At Conducting Oxide Anode Support On Titanium, Jun-Xiang He, Jin-Cheng Zhou, Kang-Ning Chen

Journal of Electrochemistry

Synthesis of butyl butyrate by direct electroxidation of n butyl alcohol and the electrochemical behaviors of several selected conducting oxide electrodes (Pb/PbO_2, Ti/PbO_2, i/SnO₂+Sb₂O₃/PbO₂ and Ti/SnO₂+Sb₂O₃+PdO_x/PbO₂) have been investigated. The results demonstrated that the intermediate layers of SnO₂, Sb₂O₃ and PdO_x could significantly decrease the interfacial resistance of the electrodes, and that the Ti/SnO₂+Sb₂O₃+PdO_x/PbO₂ electrode possessed better electrocatelytic performance than others.

Study On The Ti/Sno2/Pbo2 Anode In Sulphuric Acid Solution, Yao-Gang Li, Yan-Pin Shun, Wen-Lin Xu

Journal of Electrochemistry

The Ti/SnO₂/PbO₂ electrode, prepared by the electrodeposition method, was tested as the anode for the oxygen evolution reaction in 1 mol/L H₂SO₄ solution and examined by means of EDS, SEM and XRD. The electrocatalytic activity and the electrochemical stability of the prepared electrode were found to be superior.

Studies Of Spinal Li(1+X)Mn(2-X)O4 Rechargeable Lithium Ion Battery, Xiao-Mei Wu, Qing-He Yang, Zhong-Kao Jin, Hao-Qing Wu, Xiang-Fu Zong

Journal of Electrochemistry

The spinel Li intercalation compound Li_1+xMn_2-xO₄ (0< x <1) was prepared by using techniques of cyclic voltammetry. The electrochemical parameters of Li_1+xMn_2-xO₄ electrode vary as either the starting materials or the synthesis temperature changes. It was found that the initial capacity and reversible behaviors of the Li_1+xMn_2-xO₄ electrode depends on the amount of the excess Li, represented as x in Li_1+xMn_2-xO₄. The reversible of Li intercalation process for Li_1+xMn_2-xO₄ electrode was demonstrate by cyclic voltammograms.

Studies On The Inclusion Behavior Of Cyclodextrins With Ketoprofen By Electrochemical Methods, Jun Gu, Yong Zhang, Jin-Hao Pan

Journal of Electrochemistry

The influences of cyclodextrins and their derivatives on the electrochemical behavior of ketoprofen were studied. The inclusion constants of ketoprofen with β-CD, HP-β-CD and methyl β-CD and the influences of temperature on the inclusion actions were also investigated. The inclusion phenomena is explained with the thermodynamics parameters of the inclusion complexes.

The Study Of Poly [N-(3-Ferrocene Acetamino Propyl- Pyrrole] Film Modified Glucose Electrode, Cheng-Yun Tian, Jing Chen, Li Zhang

Journal of Electrochemistry

A poly [N-(3-ferrocene-acetamino-propyl-pyrrole)] film modified electrode was fabricated and studied by cyclic voltammetric method. The result shows that the modified electrode can give stable redox peaks of ferrocene, and an obvious catalytic peak due to glucose. This modified electrode was used to tabricate a glucose sensor which operates at +0.2 V, so that the ascorbic acid or uric acid doesn't affect the accuracy detection of glucose concentration. The sensor has a linear range of 0.1～10 mmol/L glucose, which the period of long term stability and response time of the sensor are about ten days and 2 min.

Process For Enhancing The Activity Of Amyloid Β Peptides, Kenneth Hensley, D. Allan Butterfield, John M. Carney, Michael Aksenov

Chemistry Faculty Patents

A novel process for enhancing activity of an oligopeptide or polypeptide comprising the steps of: providing an oligopeptide or polypeptide, dissolving the oligopeptide or polypeptide in an organic solvent, heating, removing the solvent, and recovering an oligopeptide or polypeptide with enhanced activity is disclosed. Also disclosed are novel oligopeptides and polypeptides enhanced by the process according the invention.

The Effect Of A Uniform Electric Field On Homogeneous Vapor–Liquid Nucleation In A Dipolar Fluid. I. Stockmayer Fluid, K.J. Oh, G.T. Gao, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

The rate of homogeneous vapor–liquid nucleation is controlled mainly by the Gibbs formation free energy of critical clusters. Within the framework of thei/υ cluster theory of Reiss and co-workers, the formation free energies of Stockmayer clusters in the presence of a uniform electric field are determined. The Helmholtz free energy of the clusters, an input required in the i/υ cluster theory, is calculated via Monte Carlo simulations. The most significant result is that as a uniform electric field is applied the formation free energy at fixed supersaturation of the vapor becomes larger than that in the absence …

Synthetic Studies Directed Toward Streptenol D: Enantioselective Preparation Of The 3,5-Diacetoxy-6E,8E-Decadiene Segment, Bireshwar Dasgupta, William A. Donaldson

Chemistry Faculty Research and Publications

The enantioselective preparation of 2-(3′R,5′R-diacetoxy-6E,8E-decadienyl)-1,3-dioxane, (+)-13, is described. This synthesis of the skeleton of streptenol D utilizes the ability of a diene-complexed (tricarbonyl)iron unit to serve as a protecting and stereodirecting functionality.

Multi-Site Proton Interactions With Natural Organic Matter, D. Scott Smith, James R. Kramer

Chemistry Faculty Publications

Water samples from various locations in Norway were used to isolate natural organic matter (NOM). The NOM was isolated using both reverse osmosis and low-pressure low-temperature evaporation for each sample site. These samples were titrated from -log[H⁺] 3 to 11 at 0.1 unit intervals. The data were analyzed using the Discrete Site Analysis (DISI) technique for pK_a intervals of 0.2. The acidity constants are grouped into four classes: strong (pK_a < 5), intermediate strong (5.1< pK_a < 7.5), intermediate weak (7.6 < pK_a < 9.2), and weak (pK_a > 9.3). All samples, regardless of isolation method, were found to contain strong and weak ligands, along with some intermediate ligands. For the same …

Fluorescence Analysis For Multi-Site Aluminum Binding To Natural Organic Matter, D. Scott Smith, James R. Kramer

Chemistry Faculty Publications

Natural organic matter (NOM) samples isolated from different water sources in Norway were compared using their fluorescence properties. Fluorescence surfaces were observed at pH 4.36 and deconvoluted using SIMPLISMA (Windig and Guilment 1991). There were a total of seven different fluorophores observed for these samples and each sampling site had between four and six ofthe fluorescent components. These components were observed to bind Al during titrations at the same pH. Multiresponse titration curves were fit using the method of Smith and Kramer (1998) and most of the binding strengths are similar to values for Suwannee River fulvic acid (1ogK’ between …