Analytical Chemistry Commons^™

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.

Indirect Ultraviolet Detection Of Biologically Relevant Organic Acids By Capillary Electrophoresis, Hong Chen, Yan Xu, Frederick Van Lente, Michael P.C. Ip

Chemistry Faculty Publications

Indirect UV detection of fourteen short-chain organic acids (e.g., oxalic acid, citric acid, malonic acid, tartaric acid, methylmalonic acid, α-ketoglutaric acid, succinic acid, ethylmalonic acid, methylsuccinic acid, glutaric acid, apidic acid, methylglutaric acid, lactic acid and pyruvic acid) by capillary electrophoresis is described. The method used phthalate as the UV-absorbing additive in carbonate buffer and the non-absorbing analytes were detected indirectly at 230 nm. The influences of buffer pH, ionic strenght, concentration of phthalate and organic modifier on indirect signal response and migration behavior of the organic acids were investigated. Comparisons of reproducibility on migration time, limit of detection and …

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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Highly Reactive Form Of Copper And Reagents Thereof, Reuben D. Rieke

Department of Chemistry: Faculty Publications

A novel Zerovalent copper species and an organocopper reagent are disclosed. The Zerovalent copper species is directly produced by reaction of a reducing agent with a combination of copper(I) cyanide or halide and an alkali metal halide salt. The organocopper reagent resulting from the reaction of the zerovalent copper species and an organic compound having one or more stable anionic leaving groups is a stable reagent that will not significantly homocouple and under controlled conditions tolerates the presence of nitrile, epoxide, imine, enone, ketone, ester, allyl and benzyl groups within the organo radical. The reagent can be controlled so that …

Artificial Maturation Of Alginite And Organic Groundmass Separated From Torbanites, Michael A. Kruge, Patrick Landais, David F. Bensley

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The two principal organic constituents — Botryococcus-related alginite and organic groundmass — were isolated by density separation from two torbanite samples (from the Stellarton Fm., Nova Scotia, Canada and the King Cannel, Utah, USA). The groundmass consisted of degraded algal, bacterial and terrestrial plant debris. Aliquots of alginite and groundmass were separately heated in gold tubes for 24 hr. with 70 MPa confining pressure, at fixed temperatures ranging between 250 and 375°C. The 250, 300 and 325°C experiments run on the alginite produced very low yields of CHCl3-extractable organic matter (EOM), indicating that very little of the generation potential …

Flash Pyrolysis Of Anthropogenic And Natural Organic Matter In Polluted Sediments, Sami T. Abdel Bagi, Michael A. Kruge, Gary L. Salmon

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

INTRODUCTION - Combustion products along with spilled petroleum and industrial chemicals contribute to environmental degradation by contaminating soils and sediments. Such anthropogenic organic matter (OM), if preserved in sediments, can serve an archival function, documenting the local, history of industrial pollution. Christensen and Zhang (1993) determined the sources of polycyclic aromatic hydrocarbons (P AH) to Lake Michigan from sedimentary records, finding that coal combustion was a major source for PAHs in these sediments. Bodzek and Luks-Betlej (1993) reported that atmospheric deposition is the main source of PAH in soils of the heavily industrialized Upper Silesia region of Poland. Smith and …

Ohmic Drop Compensation In Voltammetry:  Iterative Correction Of The Applied Potential, David O. Wipf

CAS Publications

A new method of ohmic potential drop correction for use with potential step and sweep voltammetric methods is described. The method, iterative correction of the applied potential (ICAP), essentially replaces an electronic positive feedback correction with a digital positive feedback correction. This paper will present one form of the ICAP procedure, in which voltammetric current data acquired by a high-speed digital oscilloscope are used to iteratively generate a compensating potential waveform that is then synthesized by an arbitrary waveform generator. The ICAP method is advantageous for high-speed measurements, since many of the difficulties caused by electronic positive feedback compensation are …

Highly Reactive Zerovalent Metals From Metal Cyanides, Reuben D. Rieke

Department of Chemistry: Faculty Publications

Novel zerovalent metal species and organometallic reagents are disclosed. The zerovalent metal species are directly produced by reaction of a reducing agent on a metal cyanide salt. Preferably, the zerovalent metal species are directly produced by reaction of an alkali metal reducing agent with a metal cyanide salt. The organometallic reagent results from the reaction of the zerovalent metal species and an organic compound having one or more stable anionic leaving groups.

Acidic Marine Biotoxins Implicated In Diarrhetic Shellfish Poisoning, Eoin P. Carmody

Theses

An okadaic acid (OA) etiology has been demonstrated for most outbreaks of diarrhetic shellfish poisoning (DSP) in Europe, An isomer of OA, dinophysistoxin-2 (DTX-2), has recently been found in Irish waters and, in 1991 and 1994, was the major toxin during prolonged infestations in cultivated mussels (Mytilus edulis) along the south-west coast of Ireland.

The OA class of DSP toxins have been analysed by HPLC using modified versions of three established fluorescent derivatisation methods. A ‘dual tag’ method for the confirmation of specific toxins has also been developed.

Survey work has been carried out over the past four years on …

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 …

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.

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.

Design And Performance Of The Advanced-Light-Source Double-Crystal Monochromator, G. Jones, S. Ryce, Dennis W. Lindle, B. A. Karlin, J. C. Woicik, Rupert C. Perera

Chemistry and Biochemistry Faculty Research

A new “Cowan type” double-crystal monochromator, based on the boomerang design used at National Synchrotron Light Source (NSLS) beamline X-24A, has been developed for beamline 9.3.1 at the Advanced Light Source (ALS), a windowless ultrahigh vacuum beamline covering the 1-6 keV photon-energy range. Beamline 9.3.1 is designed to simultaneously achieve the goals of high energy resolution, high flux, and high brightness at the sample. The mechanical design of the monochromator has been simplified, and recent developments in technology have been included. Measured mechanical precision of the monochromator shows significant improvement over existing designs. In tests with x-rays at NSLS beamline …

The Analysis And Isolation Of Diarrhetic Shellfish Poisoning Toxins, Seán S. Kelly

Theses

This research was initiated to examine the Diarrhetic Shellfish Poisoning (DSP) toxin profiles in mussels (Mytilus edulis) in south-west Ireland. Extensive sampling and testing of shellfish was conducted during the toxic periods of 1991 to 1994. This was the most comprehensive study ever undertaken of toxin profiles in shellfish from a single cultivation area.

A new toxin named dinophysistoxin-2 (DTX-2), which is an isomer of okadaic acid (OA), was the major toxin during prolonged DSP episodes. This toxicity in shellfish occuired soon after high cell counts of Dinophysis acuta were observed. As well as seasonal variability in toxin levels, substantial …

Preparations Of Polycarbynes, Reuben D. Rieke

Department of Chemistry: Faculty Publications

Polycarbynes prepared from a soluble source of electrons and an organic monomer or co-monomer containing at least one carbyne group in an ethereal, polyethereal, or hydrocarbon solvent are presented. A wide variety of arylcarbyne and/or alkylcarbyne monomers and co-monomers can be combined with a source of electrons soluble in an ethereal, polyethereal, or hydro-carbon solvent to form novel polycarbyne polymers. These polycarbyne polymers can be used to form synthetic diamond materials, fibers, and other materials that can withstand extreme conditions.

Preparation Of Doped Polycarbynes, Reuben D. Rieke

Department of Chemistry: Faculty Publications

Polycarbynes, such as doped polycarbynes, prepared from a soluble source of electrons and an organic monomer or co-monomer containing at least one carbyne group and, optionally, containing a doping agent, in an ethereal, poly ethereal, or hydrocarbon solvent are presented. A wide variety of arylcarbyne and/or alkylcarbyne monomers and co-monomers can be combined with a source of electrons soluble in an ethereal, polyethereal, or hydrocarbon solvent to form novel polycarbyne polymers. These polycarbyne polymers can be used to form synthetic diamond materials, fibers, and other materials that can withstand extreme con ditions.

Electrochemical Enzyme Immunoassay Using Sequential Saturation Technique In A 20-Μl Capillary: Digoxin As A Model Analyte, Noriaki Kaneki, Yan Xu, Anu Kumari, H. Brian Halsall, William R. Heineman, Peter T. Kissinger

Chemistry Faculty Publications

Capillary enzyme immunoassay with flow-injection analysis for digoxin using the sequential saturation technique has been developed. Glass capillary tubes (10 cm × 0.53 mm i.d.) with immobilized digoxin antibody were used as the immunoassay reactor. The product of enzymatic reaction. 4-aminophenol, was detected amperometrically. The digoxin and the labeled digoxin binding reaction with the immobilized digoxin antibody were completed in 2 and 10 min, respectively. Digoxin was determined in a 20-μl sample with a detection limit of 10 pg ml−1 (200 fg or 260 attomoles) and a 3 orders of magnitude range.

Highly Reactive Forms Of Zinc And Reagents Thereof, Reuben D. Rieke

Department of Chemistry: Faculty Publications

A novel zerovalent zinc species and an organozinc reagent are disclosed. The zerovalent zinc species is directly produced by reaction of a reducing agent on a zinc salt, preferably Zn(CN)₂. The organozinc reagent results from the reaction of the zerovalent zinc species and an organic compound having one or more stable anionic leaving groups. These organozinc reagents include a wide spectrum of functional groups in the organic radical, and are useful in a variety of reactions schemes.

Speciation Of Heteroatoms In Coal By Sulfur- And Nitrogen-Selective Techniquestrogen-Selective Techniques, Stephen R. Palmer, Michael A. Kruge, Edwin J. Hippo, John C. Crelling

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The peroxyacetic acid oxidation products from a series of coals of organic sulfur content 0.5-9.8 wt% were examined. The distributions of organic S and N compounds were determined by gas chromatography with sulfur-selective flame photometric and nitrogen-selective thermionic specific detection respectively. A selected sample was also examined in greater detail using low-voltage high-resolution mass spectrometry. The distribution of organic sulfur compounds in the oxidation products was remarkably similar for all the coals. The number of sulfur compounds detected was small compared with that of organic nitrogen compounds detected. This suggests that the sulfur chemistry of coal is considerably simpler than …

Fossil Charcoal In Cretaceous-Tertiary Boundary Strata: Evidence For Catastrophic Firestorm And Megawave, Michael A. Kruge

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Organic matter separated from calcareous sandstone from the upper portion of a deep-water tsunami deposit at Arroyo el Mimbral, Taumalipas (Mexico), which marks the biostratigraphically-defined Cretaceous-Tertiary boundary, consists primarily of fossil charcoal, including semifusinite and pyrofusinite. Analytical pyrolysis-gas chromatography-mass spectrometry revealed the highly aromatic and polyaromatic character of the organic matter assemblage, typical of the products of partial combustion. The organic matter probably originated as terrestrial vegetation that was caught in a firestorm and subsequently transported far offshore in the backwash of a megawave. These data are consistent with the hypothesis of combustion of large masses of vegetation triggered by …

Flash Pyrolysis-Gas Chromatography/Mass Spectrometry Of Lower Kittanning Vitrinites: Changes In The Distributions Of Polyaromatic Hydrocarbons As A Function Of Coal Rank, Michael A. Kruge, David F. Bensley

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Chemical analyses restricted to a single coal maceral permit a focus on rank effects without concern for variations in organic matter type. Vitrinite concentrates of high purity were isolated from coal samples of the Lower Kittanning seam by multi-step density gradient centrifugation, with reflectances ranging from 0.66 to 1.39% Rmax. In addition to the previously recognized losses of phenolic compounds, the vitrinite pyrolyzates exhibit marked increases in relative concentrations of tri- and tetraaromatic hydrocarbons (especially benzo[a]fluorene, methyl-phenanthrenes, methylfluorenes and methylchrysenes) above 0.9% Rmax, i.e., beyond the "second coalification jump" of Teichmüller. Thus, petrographically-recognizable physical transformations are shown …

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.

A Characterization Of Extractable, Hydroxylated Fatty Acid Bearing Components In Legionella Pneumophila, Jonathan R. Lane

Electronic Theses and Dissertations

Extraction of the lipids of Legionella pneumophila yields phases unlike those produced from other Gram-negative bacteria. A viscous interface forms between the aqueous (wash) and organic phases. More than half of the hydroxylated fatty acids were found distributed between the aqueous phase and the interfacial material, fractions in which such constituents have not been reported in other Gram-negative species. It was further observed that after the material from the aqueous/interfacial phase was dissolved in methanol or chloroform/methanol (2:1 (V/V)), the addition of acetone would create a white, flocculent precipitate. Analyses showed that the supernatant contained fatty acids that were nonhydroxylated …

Processes For Producing Doxorubicin, Daunomycinone, And Derivatives Of Doxorubicin, Desmond M. S. Wheeler

Department of Chemistry: Faculty Publications

To produce doxorubicin and its analogues methyl 3alpha, 5alpha-dihydroxy-5beta-(trimethylsilylethynyl)- 2alpha-nitromethylcyclohexane-1beta-carboxylate acetonide is condensed with 1,4-dihydro-4,4,5-trimethoxy-1-oxonaphthalene in the presence of 1,8-diazabicyclo-5.4.0]undec-7-ene in an aprotic solvent to produce 3-(2beta-carbomethoxy-4-beta-ethynyl-4-alpha, 6alpha-(di-O-isopropylidenyl)cyclohexanyl-1-yl)-nitromethyl-4,4,5-trimethoxy-1-oxo-1,2,3,4-tetrahydronaphthalene; which is cyclized to produce 9beta ethynyl-12-hydroxy-7alpha, 9alpha-(di-O-iso propylidenyl)-6-nitro-4,5,5-trimethoxy-5,5a,6- 6a,7,8,9,10,10a,11-decahydro -11-naphthacenone. The decahydro-11-naphthacenone is converted to 7alpha 9alpha,(di-O-isopropyl-idenyl)-4,5-dimethoxy-9beta ethynyl-12-hydroxy-6-nitro-6,6a,7,8,9,10,10a, 11 octahydro-11, -naphthacenone. The octahydro-11 naphthacenone is oxidized to 7alpha-9alpha, (di-O-iso propyl-idenyl)-9beta-ethynyl-11-hydroxy-4-methoxy-6- nitro-7,8,9,10-tetrahydro-5,12-naphthacenedione which is converted to 6-desoxy-6-nitrodaunomycinone, daunomycinone and related 6-substituted analogues of daunomycinone.

Preparation And Use Of (2-Butene-1,4-Diyl)Magnesium Complexes In Organic Synthess, Reuben D. Rieke

Department of Chemistry: Faculty Publications

The magnesium complexes of cyclic hydrocarbons, such as 1,2-dimethylenecycloalkanes, are readily prepared in high yields using highly reactive magnesium. Reactions of these (2-butene-1,4-diyl)magnesium reagents with electrophiles such as dibromoalkanes, alkyl ditosylates, or bromoalkylnitriles serve as a convenient method for synthesizing spirocyclic systems. Significantly, spirocarbocycles prepared by this method contain functional groups such as the exocyclic double bond or a keto group in one of the rings which could be used for further elaboration of these molecules. Furthermore, fused bicyclic systems containing a substituted five-membered ring can be conveniently prepared at high temperatures by the reactions of (2-butene-1,4- diyl)magnesium complexes with …

Soluble Highly Reactive Form Of Calcium And Reagents Thereof, Reuben D. Rieke

Department of Chemistry: Faculty Publications

A soluble highly reactive form of calcium, prepared from Ca(II) salts and a reducing agent in ethereal, polyethereal, or hydrocarbon solvents, is presented. This form of calcium can be used in the preparation of organocalcium reagents. The organocalcium reagents resulting from the reaction of the soluble highly reactive calcium with organic compounds containing either halide, cyanide, a 1,3-diene, or a polyunsaturated functionality, are stable, useful reagents for organic synthesis. The organocalcium halide reagents undergo Grignard-type reactions. They also undergo reactions with Cu(I) salts to form organocalcium cuprate reagents. The organocalcium cuprate reagents undergo a variety of cross-coupling reactions. The soluble …

Preparation Of Functionalized Polymers Utilizng A Soluble Highly Reactive Form Of Calcium, Reuben D. Rieke

Department of Chemistry: Faculty Publications

Calcium-substituted polymeric reagents are provided. These reagents can be prepared via the oxidative addition of a soluble highly reactive calcium species to organic and inorganic polymers containing alkyl, aryl, or alkylaryl pendent groups substituted with halide atoms, cyanide molecules, 1,3-dienes, or any conjugated poly unsaturated system. Preferably, the polymer is a cross linked p-bromopolystyrene, p-chloropolystyrene, p fluoropolystyrene, or chloromethylated polystyrene. Preferably, the soluble highly reactive calcium species is prepared from the reduction of Ca(II) salts with an alkali metal arene, such as lithium biphenylide. These calcium-substituted polymeric reagents react with a variety of electrophiles to yield functionalized polymers. Reaction with …