Chemistry Abstracts:

A Comparison Between Traditional and Chromatographic Adsorption Isotherms for Cotton and Cotton Derivatives. NATHAN CASTRO (El Paso Community College, El Paso, TX, 79901) STEVEN C. GOHEEN (Pacific Northwest National Laboratory, Richland, WA, 99352)

Protein adsorption can be characterized on a given surface by adsorption isotherms. Traditionally, isotherms have been developed by allowing bulk solutions to reach equilibrium with an adsorbent. It has been well established that proteins undergo a dynamic unfolding process upon contact with a surface, which may be somewhat dependent on the molecular weight of the protein, but certainly on the chemical interactions between the sorbent and surface. Adsorption is also time-dependent due to the diffusion of protein to the surface. Therefore, quantitative measure of the adhesion of protein to a surface is time-dependent. And, the data collected from traditional isotherms should reflect the equilibrium state of the protein-surface interaction. Isotherm data collected by chromatographic means, in contrast, represent different dynamics in protein-surface interactions. The protein still comes in contact with the sorbent, but the interaction contact time is lessened. This can be considered a different type of equilibrium, one that reflects a more native state of the protein. Isotherms generated by chromatographic means also differ in their shape, as well as the type of information that can be obtained. In this study, adsorption isotherms were investigated using traditional and chromatographic techniques. The data were compared. The total amount of protein adsorbed differed only slightly, and was dependent on the surface chemistry being examined. The surfaces under investigation were: an untreated cotton sample, carboxymethylcellulose (CMC) cotton, dialdehyde (DAQ) cotton and citric acid-fructose (CA-F) cotton samples. Protein adsorption of collected samples was studied utilizing a colorimetric protein assay coupled with spectrophotometric measurements of absorbance at 595 nm.

A Molten Salt Synthesis of Single Crystalline YBCO Nanorods. DARYL WONG (University of California, Berkeley, Berkeley, CA, 94720) STANISLAUS S. WONG (Brookhaven National Laboratory, Upton, NY, 11973)

YBa₂Cu₃O₇ (YBCO) is a high T_c superconductor that has potential applications in both high field magnets and superconductive circuitry. Although its utility as a high field magnet has been realized, bulk YBCO loses its high temperature superconducting ability due to low critical current densities deriving from the bulk’s polycrystalline nature which lacks directionality. One potential remedy, aligning monocrystalline subunits through material texturing techniques, can be achieved with the production of uniform, monocrystalline one-dimensional YBCO nanorod structures. The molten salt synthesis method has been shown to be a procedurally simple technique to create metal oxide nanorods. Using a molten salt method, attempts to make YBCO have been conducted with a number of yttrium, barium, and copper containing precursors which are combined with a salt, usually sodium chloride and/or potassium chloride, in varying precursor and salt ratios. These precursors were finely ground with a mortar and pestle and baked in a furnace to temperatures above the melting point of the salt. Powder x-ray diffraction (XRD) analysis was conducted to determine whether the molten salt samples contained the orthorhombic crystal structure indicative of high temperature superconducting YBCO, while scanning electron microscopy (SEM) and atomic force microscopy (AFM) images were taken to determine if a rod morphology had been formed. XRD analysis of the numerous molten salt products has shown that the desired orthorhombic YBCO nanorods cannot readily be formed, while SEM and AFM images show aggregates of nanorods and nanoparticles which vary in size. Other analytical techniques, including SQUID (Superconducting Quantum Interference Device) measurements, will be useful to further ascertain and characterize the properties of as-prepared YBCO nanorods. Because the mechanism of molten salt nanorod formation is not fully understood, creation of these desired nanorods involves a lot of experimentation with variable parameters. A more comprehensive analysis of precursors, precursor ratios, and baking temperatures should be performed before concluding the inefficacy of the use of the molten salt technique in the generation of nanoscale motifs of these superconducting materials.

A Search for Cerium Doped Lanthanum Oxide Scintillators. LATORIA WIGGINS (North Carolina A&T State University, Greensboro, NC, 27411) DR. YETTA PORTER-CHAPMAN (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

The need for new and improved radiation detectors, scintillators, is at an all time high due a progression in detection knowledge. Commonly used scintillators such as BGO and LSO have undesirable properties such as low luminosity, and slow decay times. Discovering new scintillators required literature searches, synthesizing and the characterization of compounds. The research at hand concentrated on cerium (III) doped lanthanum oxides. Compounds were synthesized using solid-state chemistry techniques such as ceramic and hydrothermal methods. Characterization consisted of x-ray diffraction, fluorescence spectroscopy and pulsed x-ray measurements. Several new inorganic scintillators were founded, however, findings concerning lanthanum oxide synthesis warrant further investigation of the compound.

A Study of Ion Exchange Resins for the Complete Separation of Cobalt, Nickel, and Copper. TRACEY WILLIS (Texas Southern University, Houston, TX, 77459) ASHLEY GARNER (Texas Southern University, Houston, TX, 77004) DR. MARGARET GOLDBERG (Argonne National Laboratory, Argonne, IL, 60439)

Age-dating of 60Co contained within "dirty" bombs can provide forensic information about the time of irradiation and possible source that leads to the constructor of the 60Co dirty bomb. The purpose of this project is to develop an analytical method for separation of transition metals, more specifically cobalt, copper, and nickel, all of which are found in the contents of these "dirty" bombs. Initial experiments will use non-radioactive metals for optimization. Separation will be performed using ion exchange chromatography, with an anionic and chelating resin using varied concentrations of acid solvents (hydrochloric and nitric). Results using the Chelex 100 resin are incomplete. Analysis was performed using high resolution inductively coupled plasma mass spectrometry (HR-ICPMS) to determine eluted concentrations of each of the ions.

Analysis of the Water-Splitting Capabilities of Gallium Indium Phosphide Nitride (GaInPN). JEFF HEAD (University of Arizona, Tucson, AZ, 85705) JOHN TURNER (National Renewable Energy Laboratory, Golden, CO, 89401)

With increasing demand for oil, the fossil fuels used to power society’s vehicles and homes are becoming harder to obtain, creating pollution problems, and are posing hazard’s to people’s health. Hydrogen, a clean and efficient energy carrier, is one alternative to fossil fuels. Certain semiconductors are able to harness the energy of solar photons and direct it into water electrolysis in a process known as photoelectrochemical water splitting. P-type gallium indium phosphide (p-GaInP2) in tandem with GaAs is a semiconductor system that exhibits water-splitting capabilities with 12.4% solar-to-hydrogen efficiency. Although this material is efficient at producing hydrogen through photoelectrolysis it has been shown to be unstable in solution. By introducing nitrogen into this material, there is great potential for enhanced stability. In this study, gallium indium phosphide nitride Ga1-yInyP1-xNx samples were grown using metal-organic chemical vapor deposition in an atmospheric-pressure vertical reactor. Photocurrent spectroscopy determined these materials to have a direct band gap around 2.0 eV. Mott-Schottky analysis indicated p-type behavior with variation in flatband potentials with varied frequencies and pH’s of solutions. Photocurrent onset and illuminated open circuit potential measurements correlated to flatband potentials determined from previous studies. Durability analysis suggested improved stability over the GaInP2 system.

Calibration for Methane Hydrate Research Unit. XIAE SHI (State University of New York at Stony Brook, Stony Brook, NY, 11790) DEVINDER MAHAJAN (Brookhaven National Laboratory, Upton, NY, 11973)

Methane hydrate, one of the most common gas hydrates, forms at low temperature and high pressure; conditions typically found below the seafloor and permafrost. Although the amount of methane hydrate trapped under the seafloor on Earth has been estimated to be enough to meet human needs for the next several hundred years, due to their dispersed nature it is very difficult to extract the hydrates1. A customized unit, named Flexible Integrated Study of Hydrates (FISH) that BNL is using for methane hydrate research, mimics seafloor conditions. In a typical process, methane gas is charged to the vessel, which initially contains a water/sediment mixture under high pressure, cooled down to 4 degrees Celsius. The hydrate formation can be visualized in the vessel through a 12-inch glass window. The kinetics of methane hydrate formation and decomposition could be studied through temperature, pressure and flow/mass meters for the duration of the experiment. The goal of my project is to test the operation and dynamics of the system, such as calibration of all flow/mass meters and BPR (Back Pressure Regulator), as well as testing the system’s cooling rate. Preliminary results show that the system is well suited for hydrate formation. Volumetric balances at the inlet and outlet reveal a discrepancy of approximately 4 ml, which is well within tolerances for experimental error. Heat transfer analyses revealed a maximum cooling rate of 0.293 ºC/hr using a tube-like heat exchanger with forced convection in conjunction with a thermally controlled water-ethylene glycol bath.

Characterization of GaInPN:Si Tandem Cells for Hydrogen Production from Photoelectrochemical Water Splitting. PAUL VALLETT (University of Vermont, Burlington, VT, 5405) DR. JOHN TURNER (National Renewable Energy Laboratory, Golden, CO, 89401)

In order for hydrogen to be part of a renewable energy infrastructure, it must be produced from a renewable energy resource. The direct photoeletrolysis of water using certain types of semiconductors have been known to split water using absorption of solar energy, but difficulties concerning efficiencies and corrosion have limited this technology. This research focused on the ability of GaInPN grown on a silicon substrate to efficiently split water. Photocurrent spectroscopy determined the band gap of the material to be 1.96 eV, which is above the necessary 1.7 eV required for water splitting. Mott-Schottky analysis, photocurrent onset, and open circuit potential were used to determine potential of the Fermi level of the system in relation to the redox potentials of hydrogen and oxygen formation. These techniques showed that the Fermi level lied just below the oxygen redox potential. The electrodes were platinized and short circuit current density measurements under air mass (AM) 1.5 illumination determined extent of water photolysis. Unbiased water splitting was achieved, at a maximum of 0.65% solar to hydrogen conversion efficiency (SHCE). Corrosion of the semiconductor in solution was determined by applying a standard current to the electrode while in solution and using profilometry to estimate the volume of semiconductor removed. On average a 0.1 µm deep well was etched into the material after 24 hours. Incident photon current efficiency (IPCE) measurements of 30% revealed that the growing process for nitrogen addition to the sample decreased the electronic properties of the material. While this system is able to produce hydrogen from water using solar power as the only energy input, and the addition of nitrogen to the material appears to have increased its durability, the material suffers a heavy loss in electronic efficiency, limiting its use in potential solar water splitting devices.

Clay Synthesis and Platinum Loading for Catalytic Applications. LEAH PRANGER (Rhodes College, Memphis, TN, 38112) KATHLEEN CARRADO (Argonne National Laboratory, Argonne, IL, 60439)

Contributions to the Catalyst Design Group were made concerning the development of synthetic clays for eventual catalytic and materials applications in three different areas. One project provides clay supports for metal species activity in catalysis. The variety of clays prepared includes silica-lithium-hectorite and tetraethoxysilane-hectorite in various dilutions. In the past, the group has used such supports in an array of projects, including loading cobalt-molybdenum-sulfide species for hydrodesulfurization and Pt(0) metal nanoparticles for oxidation catalysis. All of the samples prepared within this project were determined to be suitable for further testing. Loading of Pt(II) salts and reduction in H2/N2 atmospheres was performed. It was found that only very slight temperatures (50oC) were needed to effect reduction to Pt(0). Another task explored clay synthesis under extreme dilutions in order to foster a phenomenon called “exfoliation”. Such samples lose all their layer-to-layer registry and instead the silicate layers are randomly distributed, similar to a “house of cards” structure. These materials are useful for atomic layer deposition experiments of catalytic species commonly used within the research group. Finally, work on another layered porous material was initiated. This involved reproduction of a literature synthesis of a layered zeolite dubbed “ITQ-2”. Synthesis of these materials was performed in an autoclave under controlled temperature conditions. All materials were characterized by x-ray powder diffraction to establish crystallinity and thermal gravimetric analysis to determine water and organic contents. The Pt-loaded samples and dilute hectorites were determined to be of value for future research, while the ITQ-2 project had only partial success in synthesis.

Comparing the physical properties of ionic liquids bearing chiral and achiral hydroxyl units. JASMINE HATCHER (Queensborough Comunity college, Bayside, NY, 11364) JAMES WISHART (Brookhaven National Laboratory, Upton, NY, 11973)

Ionic liquids have generated much interest due to their potential green chemistry applications. They are considered to be environmentally friendlier solvent alternatives to traditional volatile (and hazardous) organic solvents because of their lack of vapor pressure. We report here on the synthesis and preliminary characterization of achiral and chiral ionic liquids. The chiral species were synthesized by taking a chiral auxiliary, 3-chloro-1,2-propanediol, and adding it to a tertiary amine. The achiral ionic liquids were synthesized by adding our achiral auxiliary 3-chloro-1-propanol, to a tertiary amine. Some of the tertiary amines used were DMAP (4-dimethylaminopyridine) N,N,N’,N’ tetramethyl hexadiamine. The halide salts were converted into potential ionic liquids by anion exchange. Anions studied include phosphate and bis(trifyl)imide. A large problem with many ionic liquids is that they are very viscous. Theoretically, the induction of a chiral center would reduce viscosity, however this has not been the case with the materials synthesized using 3-chloro-1,2-propanediol. Preliminary results suggest that these chiral ionic liquids are more viscous than the achiral ILS. This may be due to the presence of an extra hydroxyl group, which increases hydrogen bonding. Future work will focus on finding a new chiral auxiliary and comparing the properties of racemic vs. enatiopure ionic liquids.

Controlled Synthesis, Characterization, and Properties of Tin Oxide Nanoparticles. JENNIFER CODDING (McMurry University, Abilene, TX, 79697) WEI WANG (Oak Ridge National Laboratory, Oak Ridge, TN, 37831)

Tin oxide nanoparticle based materials have various applications as sensors, catalysts, pigments, and electrode materials. Physical and structural properties, along with crystallinity and particle size and morphology of the tin oxide nanoparticles, depend on the method of synthesis. In this research, tin oxide nanoparticles were synthesized by forced hydrolysis of Tin(IV) chloride in a hydrochloric acid-alcohol aqueous solution. The use of alcohols in the synthesis of tin oxide nanoparticles provided the ability to correlate procedures of experimental synthesis with the properties of the desired compound. A systematic study was performed to examine nanoparticle formation at different conditions by varying the type of alcohol, alcohol/water ratio, reaction temperature, and time. Dynamic Light Scattering was used to verify the size and distribution of the particles and a UV-visible spectrometer was used to measure absorption to determine the temperature at particle appearance. Experiment shows that tin oxide nanoparticles form in alcohol-water media with alcohol volume fractions below thirty percent, and that particle size increases with a decrease in alcohol percentage. In an ethanol-water mixture, particle formation initiates at 84ºC in thirty percent alcohol, while particles develop at 86ºC in twenty-five percent alcohol in a methanol- or butanol-water mixture and at 85ºC in twenty percent alcohol in an iso-propanol or n-propanol-water mixture. Particle size and concentration also increase with an increase of reaction time above the formation temperature. Under uniform conditions, the size of the nanoparticle is directly proportional to the size of the alcohol molecule. Additional experiments are needed to determine more precisely the required time versus temperature ratio for the controlled synthesis of nanoparticles. Ultimately, forced hydrolysis is a good method to control the size and shape of discrete tin oxide colloidal nanoparticles.

Decoherence Effects in Semi-Classical Trajectory Simulations of CH2 Mixed States. LAURA FREDRIKSEN (State University of New York at Albany, Albany, NY, 12222) TREVOR SEARS (Brookhaven National Laboratory, Upton, NY, 11973)

The collision-induced intersystem crossing between the singlet (ã ¹A₁) and triplet (X ³B₁) states of methylene (CH₂) is crucial to the realistic modeling of combustion systems, since these two forms of methylene have distinct reactivities and product branching ratios. It is currently thought that this process occurs through collisions involving a few special "gateway states" occurring in pairs that are quantum mechanical mixtures of singlet and triplet. Recent laser kinetic spectroscopy experiments have identified a previously unrecognized collisional process that evidently interconverts the two components of each mixed state pair efficiently. A possible mechanism for this process is being explored theoretically. A differential phase shift of the singlet and triplet components of a single mixed state may be induced by a rare gas collision, resulting in population transfer to the mixed-state partner. A semiclassical trajectory study of this decoherence process is being used to assess the consistency of this proposed model with the experimental observations.

Designing Cyclic Polyammonium Salts for Potential Uses as Anionic Receptors. ALEJANDRA CASTANO (Queens College, Flushing, NY, 11367) JAMES WISHART (Brookhaven National Laboratory, Upton, NY, 11973)

The goal of this project is to synthesize cyclic polyammonium compounds that will be able to accommodate an electron as a guest. There have been several reports of cyclic ammonium polycations used as receptors for anionic guests such as chloride. The newly synthesized anion receptors will be used to control the solvation environment for excess electrons generated by pulse radiolysis. Providing a well-defined environment for the electron will help us to understand (by comparison) how the electron is solvated in bulk liquids (ionic and molecular) where the environment is highly disordered. The cyclic cations were synthesized by reacting tertiary diamines such as diazabicyclo[2.2.2]octane (Dabco) and N,N,N’,N’-tetramethylbutanediamine with dihaloalkanes to produce the polyammonium cyclic adducts. These polyammonium halide salts were then converted to bis(trifluoromethylsulfonyl)imide salts and were investigated as potential ionic liquids. Preliminary NMR and Mass Spectrometry results indicate that the target cyclic polyammonium compound was not isolated using current reaction conditions. There is evidence that the product isolated is an ionene polymer. Differential Scanning Calorimetry (DSC) and Mass Spectroscopy analysis of this polymer is reported. Future work will focus on synthesizing cyclic polyammonium salts using different reaction conditions and analyzing the products using NMR spectroscopy, elemental analysis, Mass Spectrometry and pulse radiolysis techniques.

Detection of botulinum toxin using a sandwich assay with quantum dots as the fluorophore. ABBY TYLER (Utah State University, Logan, UT, 84321) MARVIN WARNER (Pacific Northwest National Laboratory, Richland, WA, 99352)

Development of assays and technology for biological toxins is a priority in the world today. Botulinum toxin is a potential bioterrorism agent for which new detection technologies are being developed. Effective detection systems need to have high sensitivity, and be rapid, automated, and accurate. Automated fluidics systems using sandwich immunoassays for detection have been developed at PNNL to fulfill these requirements. In order to increase sensitivity of biotoxin detection, quantum dots are used as the fluorophore. Quantum dots, or semiconductor nanocrystals, are becoming widely used in bioimaging but their use in biodetection is relatively new. Some advantages of quantum dots are good photostability, and a broad excitation spectrum and narrow emission spectrum that is highly red-shifted compared to the excitation wavelength. A fragment of the botulinum neurotoxin was used in these studies as well as two antibodies that are specific for different epitopes on the toxin. One antibody was coupled to several types of beads and the other antibody was coupled to the quantum dot. Bench top sandwich assays were performed by mixing the antibody-labeled beads, a sample of the toxin fragment, and antibody-labeled quantum dots. After reacting and washing this mixture, the fluorescent response was recorded. Assays were also done by packing a column of antibody-labeled beads in a cell in the automated fluidics system, perfusing a sample of toxin over it, then perfusing the fluorophore over it. Detection of 10pM toxin in buffer was achieved using the bench top assay with Sepharose 4-B beads and 655nm quantum dots with a fifteen minute reaction time. Polyacrylimide beads were used for detection using the automated system. Detection limits were slightly higher and there was more variability in the on column assay. Quantum dots have been an effective reporting agent in the bead based sandwich immunoassay for botulinum toxin.

Determination of Aerosol Particle Size and Chemical Composition Using an Aerodyne Aerosol Mass Spectrometer. RY FORSETH (University of Wisconsin-Madison, Madison, WI, 53715) YIN-NAN LEE (Brookhaven National Laboratory, Upton, NY, 11973)

Aerosol particles serve diverse roles in the earth’s atmospheric processes including cloud formation, acid rain production and climate change through radiative forcing. In order to understand and predict aerosol’s distributions and effects in the atmosphere, it is important to determine the chemical composition of aerosol particles, including nitrate, sulfate, ammonium, and organics, to elucidate their sources and formation mechanisms. Consequently, it is highly desirable to gather fast real-time data of atmospheric aerosol concentration and composition. To accomplish this, we have carried out experiments using a new real-time Aerodyne Aerosol Mass Spectrometer (AMS) to study ambient samples as well as laboratory generated aerosol standards of know composition. We have thus gained a better characterization of the AMS regarding its ability to quantify the individual chemical components and to differentiate classes of organic compounds. Specifically, the AMS was compared with a particle-into-liquid sampler-ion chromatography (PILS) technique to gauge the qunatitativeness of the AMS's analysis. In addition, since the AMS mass fragment data contain information that can be used to classify organics depending on their degree of oxidation, we have performed AMS analysis of laboratory generated organic aerosols of different oxygen to carbon ratios to provide additional data to corroborate this analysis scheme. It was found that the AMS underestimates the mass loading of aerosol particles in both ambient and lab measurements, and ambient aerosols are comprised mainly of OOA. Fresh diesel emissions were found almost completely comprised of HOA. These finding direct us to conduct further studies to probe into why there is a discrepancy between the PILS and AMS. Finally, our findings illustrate a need to use different organic species of various degrees of oxidation and functional groups to gain insights into the chemical characteristics of OOA and HOA.

Determination of Binding Constants Between Thiourea Anion Receptors and Selected Monovalent Anions. ALICIA POWERS (Georgia Institute of Technology, Atlanta, GA, 30332) LÆTITIA DELMAU (Oak Ridge National Laboratory, Oak Ridge, TN, 37831)

The selective extraction of anions, particularly those in nuclear waste, is desirable because some anions hinder waste processing. Anion receptors can increase anion extraction and can possibly exhibit selectivity when designed from ligand modeling calculations. In this project, three thioureas, chosen for their geometry and ability to develop hydrogen bonds with anions, are compared as anion receptors for several monovalent anions—nitrate, chloride, bromide, iodide, bicarbonate, and perchlorate—by measuring the binding constants between each thiourea and anion. Radiotracer experiments are used to measure the distribution of cesium between the organic and aqueous phases at varying initial concentrations of cesium for systems with and without anion receptors. Data from these experiments is modeled using the Fortran modeling program SXLSQI. In this program the predicted species formed in the organic phase are entered and the binding constants are calculated. The stoichiometry of the predicted species is varied in order to determine which model best fits the obtained data. Electrospray mass spectrometry (ESMS) is used to provide further evidence that the species used in the model are the actual species formed. Results show that all of the thioureas increased cesium extraction for all anions except perchlorate, although the order of the amount by which the thioureas increased extraction varied by anion. Most of the systems were best modeled with one thiourea binding to each monovalent anion although some were best modeled by both one and two thioureas binding to each anion. ESMS results for the nitrate anion with one of the thioureas showed that nitrate did bind to one thiourea although some nitrate also bound to two thioureas. These results show that thioureas were successful both in increasing anion extraction and in selectively extracting certain anions.

Determination of Forcefield Parameters to Evaluate the Binding of Porphyrin Structures to c-type Cytochrome Architectures. ADRIENNE EASTLAND (Chicago State University, Chicago, IL, 60628) DR. DAVID TIEDE (Argonne National Laboratory, Argonne, IL, 60439)

The binding of porphyrin-like molecules to the surface of c-type cytochrome proteins allows the initiation of electron transport. In order to develop biomimetic photosynthetic devices, the initiation step must be tuned by the choice of substituents on the porphyrin molecules. Computational docking studies combined with experimental fluorescence studies allow the evaluation of the effects of substituent changes on electron transport rates. The aim of this work is to develop a scoring function that is fast enough to be successfully applied to the prediction of the binding energy of a c-type cytochrome to a porphyrin-like ligand. Docking studies depend heavily on the scoring function employed. By using ab initio calculations at the Hartree Fock//6-31G* level, bond, angle, and dihedral parameters for the CHARMM scoring function were developed for a series of small molecules, representative of functional groups found in organic and biochemical systems. Upon parameterization, the dihedral force constant, k, for the CA-CC-OC-OC dihedral in carboxybenzene was determined to be 3.66 kcal/mol/degree with n = 2 (n is the multiplicity of the function). For naphthalene dicarboxylate k = 1.16 kcal/mol/degree with n = 4. The magnitudes of the k values are in good agreement with existing CHARMM forcefield parameters. Furthermore, these values reproduce the quantum mechanical energy profiles as a function of angle with R2 values of 0.97 and 0.94 for the carboxybenzene and naphthalene dicarboxylate molecules, respectively. A successful method will bridge the gap between expensive free-energy simulations and empirical scoring functions that are currently used to predict binding energy.

Determination of the Efficiency of Mixed-Acid Digestions of Sediments. ALEJANDRA HUERTA (Hartnell Community College, Salinas, CA, 93901) GARY GILL (Pacific Northwest National Laboratory, Richland, WA, 99352)

Mixed-acid digestion is a method often used for the determination of elemental analysis of sediment samples. It is crucial that efficiency details associated with the digestion method be well understood on an element by element basis. Battelle’s Marine Sciences Laboratory Standard Operating Procedure for Sediment Mixed-Acid Digestions was modified to identify conditions which produce optimal recovery of elements. The parameters that were adjusted for testing were mass of sediment, mixed-acid volume, mixed-acid composition and digestion time. Digestion involves treatment of the sediment sample with mixed-acid mixtures at 135° C ± 10° in a Teflon® digestion bomb. Typical analytical methods include Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and Inductively Coupled Plasma - Mass Spectrometry (ICP-MS). Initial experiments involved determining the optimal ratio of acid volume to mass of sediment. Experiments were designed to identify the point at which insufficient acid was used to effectively digest a given mass of sediment. When the mass of sediment was varied between 0.2 and 1.0 gram using a 4 mL aqua regia acid mixture (3 mL hydrochloric acid and 1 mL nitric acid), there was no effect on the recovery of the elements Al, Ba, Ca, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sr, Ti, V, and Zn. The next experiments focused on a time study to resolve the shortest digestive time for optimal elemental recovery. Two masses of sediment were investigated, 0.25 and 0.7 g, again utilizing aqua regia digestion (4 mL). Maximum recovery was reached after 4 hours of digestion; additional digestion time released no or only minimal amounts of elements from the sediments. The final set of experiments was designed to identify optimal conditions for the total digestion of sediment using a mixture of hydrochloric acid, nitric acid, hydrofluoric acid, hydrogen peroxide, and boric acid. These experiments were designed to determine the optimal volume of hydrofluoric acid needed to achieve a total digestion. Utilizing two masses of sediment 0.25 and 0.5 g and varying the volume of hydrofluoric acid and boric acid. Total digestion was achieved with a minimum volume of 0.5 mL hydrofluoric acid and a .25 g of sediment. Future experiments incorporating the findings in these experiments will be executed using a heated carbon block as the source for thermal energy.

Determination of the Electrostatic Potential of Cytochrome c7. BRIAN WRIGHT (Chicago State University, Chicago, IL, 60426) DAVID TIEDE (Argonne National Laboratory, Argonne, IL, 60439)

Assemblies of c-type cytochromes may be capable of long-range electron transport and thus are being considered as components of electron transfer/energy storage devices. The electron transport mechanism requires the binding of a small porphyrin-like molecule to initiate the electron transfer. In order to determine the likely binding sites on the surface of c-type cytochromes, the electrostatic potential of cytochrome c7 taken from Geobacter sulfurreducens (Protein Data Bank entry 1OS6) and horse heart cytochrome c7 (Protein Data Bank entry 1HRC) were calculated by solving the Poisson-Boltzmann equation using Delphi, a program that is integrated into the Chimera molecular modeling program. These calculations allow the identification of electron-rich or electron-poor sites that should contribute to binding. Results with model 1HRC showed good agreement with literature values, validating the charge and radii parameters chosen for the calculation. The overall surface of cytochrome c7 in model 1OS6 is positively charged by the amino acid lysine (Lys) (electron poor). The amino acids aspartic acid and glutamic acid contribute to the negative charge (electron rich) of the 1OS6 model. One possible binding site is located near Lys-64, Lys-52, and Lys-9. Another possible binding site is near Lys-37, Lys-33, and Lys-29. These areas are been considered as binding sites because the surface may provide prophyrin-like molecules large enough areas to bind. The ability to determine which parts of the c-type cytochrome are involved in the binding will lead to an improved understanding and control of the electron transfer process.

Development of Optical Trapping Raman and Coherent Anti-Stokes Raman Scattering (CARS) Spectroscopy for Analysis of Phospholipid Vesicles. DANIEL AUTREY (Fayetteville State University, Fayetteville, MC, 28301) DR. JAMES W. CHAN (Lawrence Livermore National Laboratory, Livermore, CA, 94550)

Raman spectroscopy is a powerful technique that is being applied to the study of biological systems in our laboratory. Raman spectroscopy is a laser-based method of chemical analysis that generates vibrational signal from molecular bonds. There are two overall goals of this project. The first aim is to obtain the spontaneous Raman signatures of individual optically-trapped phospholipid vesicles. Two types of phospholipids are analyzed in this experiment, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). Single 0.4 µm diameter phospholipid vesicles are successfully trapped in a laser-trapping Raman system and their spectral signatures simultaneously acquired. Additional experiments were carried out to determine the vibrational modes of DPPC that are sensitive to the gel-liquid crystal phase transition occurring at 41°C. Characterization of the DPPC phospholipids in the liquid crystal state is important to understanding the permeability of the lipid membrane. After the phase transition, a noticeable slight shift in the CH₂ deformation mode from 1462 cm^-1 to 1458 cm^-1 occurs which may be explained by a weakening of the dispersion forces between neighboring phospholipids, allowing the CH₂ groups to vibrate more freely. The second aim of this project is to develop a broadband coherent anti-Stokes Raman scattering (CARS) optical trapping system to enable the monitoring of rapid biological processes. To achieve this end, the laser conditions necessary to generate broadband light by the coupling of femtosecond pulsed near-infrared light into a photonic crystal fiber (PCF) was investigated.

Development of Optical Trapping Raman and Coherent Anti-Stokes Raman Scattering (CARS) Spectroscopy for Analysis of Phospholipid Vesicles. SALIMA HAMED (Fayetteville State University, Fayetteville, NC, 28301) JAMES W. CHAN (Lawrence Livermore National Laboratory, Livermore, CA, 94550)

Raman spectroscopy is a powerful technique that is being applied to the study of biological systems in our lab. Raman spectroscopy is a laser-based method of chemical analysis that generates vibrational signal from molecular bonds. There are two overall goals of this project. The first aim is to obtain the spontaneous Raman signatures of individual optically-trapped phospholid vesicles. Two types of lipids are analyzed in this experiment, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and (DMPC). Single 0.4 µm diameter lipid vesicles are successfully trapped in a laser trapping Raman system and their spectral signatures simultaneously acquired. Additional experiments were carried out to determine the vibrational modes of DPPC that are sensitive to the gel-liquid crystal phase transition occurring at 41°C. Characterization of the DPPC phospholipids in the liquid crystal state is important to understanding the permeability of the lipid membrane. After the phase transition, a noticeable slight shift in the CH₂ deformation mode from 1462 cm^-1 to 1458 cm^-1 occurs which may be explained by a weakening of the dispersion forces between neighboring phospholipids, allowing the CH₂ groups to vibrate more freely. The second aim of this project is to develop a broadband coherent anti-Stokes Raman scattering (CARS) optical trapping system to enable monitoring rapid biological processes. To achieve this end, the laser conditions necessary to generate broadband light by the coupling of femtosecond pulsed near-infrared light into a photonic crystal fiber (PCF) were investigated.

Development of Optical Trapping Raman and Coherent Anti-Stokes Raman Scattering (CARS) Spectroscopy for Analysis of Phospholipid Vesicles. BETHANY WEISS (Fayetteville State University, Fayetteville, NC, 28301) DR. JAMES W. CHAN (Lawrence Livermore National Laboratory, Livermore, CA, 94550)

Raman spectroscopy is a powerful technique that is being applied to the study of biological systems in our lab. Raman spectroscopy is a laser-based method of chemical analysis that generate vibrational signal from molecular bonds. There are two overall goals of this project. The first aim is to obtain the spontaneous Raman signatures of individual optically-trapped phospholid vesicles. Two types of lipids are analyzed in this experiment, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). Single 0.4 µm diameter lipid vesicles are successfully trapped in a laser trapping Raman system and their spectral signatures simultaneously acquired. Additional experiments were carried out to determine the vibrational modes of DPPC that are sensitive to the gel-liquid crystal phase transition occurring at 41°C. Characterization of the DPPC phospholipids in the liquid crystal state is important to understanding the permeability of the lipid membrane. After the phase transition, a noticeable slight shift in the CH₂ deformation mode from 1462 cm^-1 to 1458 cm^-1 occurs which may be explained by a weakening of the dispersion forces between neighboring phospholipids, allowing the CH₂ groups to vibrate more freely. The second aim of this project is to develop a broadband coherent anti-Stokes Raman scattering (CARS) optical trapping system to enable monitoring rapid biological processes. To achieve this end, the laser conditions necessary to generate broadband light by the coupling of femtosecond pulsed near-infrared light into a photonic crystal fiber (PCF) was investigated.

Distribution coefficients of several ion-exchange resins for the separation of cobalt, nickel, and copper. JILLIAN SMITH (East Stroudsburg University, East Stroudsburg, PA, 18301) MARGARET GOLDBERG (Argonne National Laboratory, Argonne, IL, 60439)

A method for the separation and accurate quantification of cobalt, nickel and copper is needed for the age dating of certain irradiated substances. The separation will be completed by using ion-exchange chromatography. The objective of this project was to measure the distribution coefficients for cobalt, nickel, and copper as a function of acid concentration and resin (Chelex 100, AG 1-X8, AG MP-1 and AG 50W-X8) using batch ion-exchange. The equilibrium of the metal ions between the aqueous phase and the ion-exchange resin is represented by the distribution coefficient (KD). Initial and final concentrations of the cations were measured by using high resolution inductively coupled plasma-mass spectrometry. The project, however, was halted when the results showed an apparent contamination of the analyzed final concentrations. With only one quarter of the samples run, further research is necessary to correct the calibration curve and to account for the interferences of the matrix before any more quantification is performed.

Effect of trypsin stability on efficiency of protein digestion in mixed aqueous-organic solvents. JASON ASKEW (Arizona State University, Tempe, AZ, 85281) VLADIMIR KERY (Pacific Northwest National Laboratory, Richland, WA, 99352)

Trypsin digestion is most the widely used method for sample preparation to identify proteins using mass spectrometry. Typically, proteins are denatured by chaotropic salt such as urea or guanidine to increase yield and quality of the digestion. Alternatively organic solvents such as acetonitrile or methanol are be used for protein denaturation. Using trypsin digestion in mixed aqueous -organic solvents has advantages over urea in shorter procedure and not using extra cleaning step. However higher concentrations of organic solvents can quickly denature trypsin causing incomplete protein digestions. Therefore we investigated the effect of organic solvents (methanol and acetonitrile) on trypsin stability by measuring trypsin activity using a low molecular weight (BAPNA, benzoylaarginil para nitroanilid) and high molecular weight substrates (bovine serum albumin, casein). While trypsin activity diminished almost instantly at higher organic solvent concentrations (60-80%) by using BAPNA, the activity measured with the protein substrate remained comparable to that of in water at higher protein concentrations but decreased at lower protein concentrations. It appears that the protein substrate stabilizes trypsin and prevents its denaturation in solvents with high concentration of organics. Therefore it is important to maintain higher concentrations of protein in trypsin digestions to obtain good digestion and high yield of digested peptides. Our observation thus makes important implications for optimization of trypsin digestions for mass spectrometry sample preparation in mixed aqueous-organic solvents.

Effects of Microbial Activity on the Stability of Apatite. DIANNA MANJARREZ (Pacific Lutheran University, Tacom, WA, 98447) DAWN M. WELLMAN (Pacific Northwest National Laboratory, Richland, WA, 99352)

A proposed remediation technology is to immobilize uranium by injecting a soluble phosphate amendment into the contaminated soil. The addition of a soluble phosphate amendment would initially form autunite, the dominant uranyl-phosphate mineral, to directly immobilize uranium and prevent further migration through the subsurface. Secondary to this, apatite will precipitate within the subsurface serving as a long-term sink for uranium via sorption and/or precipitation of uranium phosphate minerals. The environmental stability of apatite has been the subject of numerous investigations. Although the results of these investigations have provided valuable information regarding the mechanisms and rates of apatite corrosion as a function of relevant environmental variables, the effect of microbial activity on the durability of apatite has been the subject of far fewer investigations. This investigation quantifies the effect of microbial activity on the degradation of apatite at T = 23°C, pH 6-8. Preliminary results suggest pH does not affect the release of calcium or phosphorus from apatite. Also, the presence or absence of microorganisms did not have a significant effect on the reaction progress, as indexed by calcium or phosphorus, in the presence or absence of aqueous phosphorus. The formation of secondary phase formation is possible and is the subject of further investigation.

Effects of Reaction Time upon Mesoporous Carbon Self Assembly. LAURA WANAMAKER (Middle Tennessee State University, Murfreesboro, TN, 37132) SHENG DAI (Oak Ridge National Laboratory, Oak Ridge, TN, 37831)

Mesoporous carbon materials, which have a wide range of applications, have previously been synthesized using silica scaffolds, which are fabricated from surfactant templates. This method, however, is very inefficient as it involves the waste of silica scaffolds and surfactant templates and the use of toxic chemicals for silica removal. Thus, a method has been developed using surfactants as direct templates for the synthesis of the carbon materials. As prescribed by this method, triblock copolymers were used as the surfactant templates and a phloroglucinol/formaldehyde copolymer was used as a carbon precursor. These triblock copolymers are ideal for use in this process as they provide for carbon through self-assembly under mild conditions. Also, they permit the production of carbon materials as monoliths, fibers, sheets, and films. In addition, this method allows for the management of pore size and structure of the carbon materials by regulation of concentration and the specific surfactant used, respectively. The purpose of the current research was to determine the optimal reaction time to produce carbon materials composed of polymers of predetermined sizes and of uniform pore size. Reaction times were varied between 20 minutes and 2 hours to determine the dependence of the self-assembly process. This process of polymerization of phloroglucinol/formaldehyde copolymers induced phase separation into an aqueous, inorganic layer, which was discarded, and an organic layer. The organic layer was separated out and dried at 80°C overnight and then at 140°C overnight prior to carbonization. Nitrogen absorption/adsorption measurments, although pending, will provide pore size, pore volume, and surface area of the produced carbon material.

Energetics of charge separation reactions as a function of solvent polarity. JUAN ALICEA (Dowling College, Oakdale, NY, 11769) JOHN R. MILLER (Brookhaven National Laboratory, Upton, NY, 11973)

Energetics of charge separation reactions in highly polar media containing electrolytes are accurately determined from the differences of readily measured redox potentials and a Coulomb term. However, energetics change in less polar media due to changes in solvation energies, and can be crudely estimated using the Born equation or computational chemistry techniques, but are not readily measured. In order to provide accurate energies for charge separation reactions in specific systems and calibrations for computational chemistry techniques, this project examined the reduction of quinones as a function of solvent polarity. Quinones in tetrahydrofuran (THF) and acetonitrile were titrated with the metallocene reducing agents cobaltocene or decamethylferrocene. Continuous wave spectra from 200-900 nm were obtained after each addition of the reducing agent. Absorption peaks corresponding to the quinone anions were quantitatively analyzed to determine the equilibrium constant and thus the free energy of the single electron transfer. The spectra indicate that some molecules exist as free ions in solution, whereas others appear to form ion pairs or charge transfer complexes. To further study the dissociation of the quinone and reducing agent ion pairs, continuous conductivity was measured. In acetonitrile the conductivity measurements of benzoquinone titrated with cobaltocene indicate complete dissociation. However, in THF the reduction yielded only a fraction becoming free ions. The experiment was repeated with other metallocene-quinone pairs that have a variety of reduction potential differences. The plot of conductivity as a function of decamethylferrocene concentration for the titration of flouranil in both THF and acetonitrile gives a curve that may be explained by an equilibrium between free ions and paired ions. Further investigations seek to determine equilibrium constants for the formation of ion pairs and for the dissociation of ion pairs into free ions. Examination of the energetics of electron transfer in medium and low polarity solvents for quinone-metallocene redox pairs should enable generalizations to be made about such energies for other molecules as a function of solvent polarity.

Exploration of using Starch as a Recovery Agent for Catalytic Iodine. BEN SIKORA (Colorado School of Mines, Golden, CO, 80401) JOHN VERKADE (Ames Laboratory, Ames, IA, 50011)

Currently a method for conjugating soybean oil is being developed that uses Iodine as a catalyst. To help conjugated soybean oil be more economically comparable to other oils, on the industrial scale, Iodine must be able to be recycled. A survey of a variety of starches and mixtures of these starches with water at various concentrations has been conducted to obtain optimum conditions for the removal of Iodine from Hexanes, and subsequent recovery from the starch. When potato starch was used it was found that it worked best when only wetted. The wetted potato starch gave the fastest absorption time of Iodine out of Hexanes, but posed problems when trying to drive the Iodine back out of the starch by thermal decomposition of the starch-Iodine complex. "V" modified starch was found to work without an outside solvent, such as water. This helped make the removal process of Iodine much simpler by removing the need to separate another liquid from the process. The results obtained for driving Iodine out of the starch were different from literature insight in the fact that literature suggests that Iodine will leave the starch under thermodynamic activation. Some complications are still perplexing and require future investigation, such as the best process to remove the Iodine from the starch back into the Hexanes for recycling.

Extraction of Actinide Elements. SARA MONTGOMERY (Rochester Institute of Technology, Rochester, NY, 14623) JEFF GIGLIO (Idaho National Laboratory, Idaho Falls, ID, 83415)

Advanced fuel specimens of the Materials and Fuel Complex (MFC) containing Plutonium, Americium, Neptunium, and Zirconium are prepared and sent to the Advance Test Reactor (ATR) and exposed to neutron bombardment. Characterization is performed on fuel stock material products before fabrication of metallic rods, before irradiation, and post irradiation (PIE). Characterization of the fuel samples is complicated because of isobaric interferences using inductively coupled plasma mass spectrometry (ICP-MS). In addition, background complications and wavelength overlaps complicate analyses by inductively coupled plasma atomic emission spectroscopy (ICP-AES). To minimize interferences, and reduce the overall actinide content of the samples (ALARA considerations) a means of separating the actinides from each other and removal of the actinides from a sample (i.e. "Clean-up) is needed. The objective to the research was to simplify separation schemes using TRU™ resin and manual Gas Pressurized Extraction Chromatography. The removal of the actinides will allow for more accurate and safer analysis of fuel samples for trace element impurities (before irradiation) and fission products after irradiation. The TRU resin worked well for the retention of Pu and U. However, Np proved to be problematic. More work is needed to fix the oxidation state of the Np for better retention. The removal of Pu from the TRU resin was accomplished. However, the U was not removed from the resin material with the acid used. The TRU resin worked well in the “Clean-up” of the actinides.

Froth Flotation and Other Means of Separation of Plastics of Equal Density and/or Similar Characteristics. MICHAEL MAJEWSKI (University of Pittsburgh, Pittsburgh, PA, 15213) BASSAM JODY (Argonne National Laboratory, Argonne, IL, 60439)

Froth flotation is a method of using the hydrophobic and hydrophilic properties of materials to selectively attach air bubbles to one type of polymer in a mix, allowing for separation. By manipulating surface tension, acidity/basicity and specific gravity of solutions, it is possible to isolate, purify, and clean polymers from various shredder residues into high value resin streams. Plastics that are of interest include polypropylene (PP), talc-filled polypropylene (PP w/Talc), polyethylene (PE), acrylonitrile-butadiene-styrene copolymer (ABS), and ABS-polycarbonate alloys (ABS-PC). After submersion in successive solutions in which some plastics float and others sink due to the previously mentioned parameters and froth flotation, individual fractions form, each with a high purity in one or more thermoplastics. After experimentation, FTIR spectroscopy, as well as some FT-Raman, is used to identify the polymers. Difficulty arises in the isolation of polymers from shredder residue, as numerous contaminants include oils, gasoline, other automotive and appliance fluids, foam, and metals. What is received as bulk shredder residue destined for a landfill can be processed, cleaned, pelletized, and re-molded. A PP/PE product has been isolated. Interior automotive plastic components, such as battery trays and knee bolsters, have been molded from the recycled material. I have spent time in the lab doing wet chemistry, including froth flotation and density separation, on various polymers, air classification using air columns, FTIR analysis to identify plastics, and measurements of the surface tension and specific gravity of solutions.

Functionalization of a Ceramic Membrane for Liquid-Liquid Extraction. DERRICK WHITLOCK (Texas Southern University, Houston, TX, 77095) SETH SNYDER (Argonne National Laboratory, Argonne, IL, 60439)

Ethanol, a product available in large quantity from corn fermentation, has been proposed as a viable alternative for gasoline. However, major barriers to the successful implementation of ethanol as a major fuel source are high costs and energy consumption associated with routine distillation of aqueous mixtures. Hydrophobic membranes, which have been employed successfully in liquid-liquid extraction, should offer a viable alternative to distillation. Herein, we disclose a process using ethyltrimethoxysilane (EtTMS) to functionalize ceramic membranes capable of separating ethanol from water with high flux and minimal energy costs. Overall hydrophobicity analyses conducted on functionalized ceramic test membranes indicated the development of successful and versatile hydrophobic functionalization protocol and the measurement of negligible H₂O flux.

Imaging Brain Amyloid after Traumatic Brain Injury and Drug Use with [11C] 6-OH-BTA-1 (PIB). CANDACE GIRARD (Springfield Technical Community College, Springfield, MA, 1056) JOANNA FOWLER (Brookhaven National Laboratory, Upton, NY, 11973)

Cerebral deposition of Β-amyloid present in amyloid plaque (AP) may present an early and necessary step in the pathogenesis of Alzheimer’s disease (AD). Postmortem immunohistochemical analysis after traumatic brain injury (TBI) also indicates the presence of AP. Recently, [N-Methyl-¹¹C] 2-(4´-(Methylamino) phenyl-6-hydroxy-benzothiazole (6-OH-BTA-1), commonly known as PIB, was introduced as a high affinity ligand for imaging AP with Positron Emission Tomography (PET). In the present study, the synthesis and radiolabeling of PIB was accomplished according to modified published procedures. Using PIB for in vitro autoradiography studies, assessments of AP concentration from TBI specimens were evaluated. Frozen rat brain (5=injured, 4=normal) sections were exposed to Β-sensitive PhosphorImager plates for 40+ min. The exposed plates were scanned in a PhosphorImager to produce digital images indicating high densities of ligand binding in the white matter regions of normal and injured rats. The presence or absence of group differences in grey matter areas awaits quantitative and statistical analysis. Additionally, PIB was used for the first in vivo evaluation of AP concentration secondary to Methamphetamine abuse using PET imaging. A male Sprague-Dawley rat (250g) was pretreated with Methamphetamine for 5 consecutive days. [¹¹C] PIB was administered intravenously and a 90 minute dynamic PET scan recorded PIB uptake in specific brain regions. The highest levels of labeled PIB binding were in the corpus striata. These findings are preliminary and are part of an ongoing study to develop novel therapeutic strategies for drug abuse and treatment.

Improved Sample Preparation for Metabolites of Organophosphorus Insecticides in Biological Matrices. MELISSA PURPURA (New Mexico State University, Las Cruces, NM, 88003) JAMES A. CAMPBELL (Pacific Northwest National Laboratory, Richland, WA, 99352)

Organophosphorus insecticides are broadly used in a variety of applications. Because of their widespread use, the potential exists for both occupational and environmental exposures that may cause a variety of health problems due to the inhibition of the enzyme acetylcholinesterase. The measurement of known metabolites in biological matrices through biomonitoring is a means for determining exposure to parent organophosphorus pesticide compounds. However, biological matrices present a unique challenge for analysis due to the potential interferences from compounds they contain. For this reason, methods for the purification and analysis of three metabolites of chlorpyrifos (diethylphoshate, trichloropyridinol, and diethylthiophosphate) were studied using whole rat blood. Techniques such as liquid-liquid extraction with solvents of varying polarity, centrifugation, and filtration were used in order to purify the samples and their extracted residues. All samples were derivatized and analyzed by gas chromatography/mass spectrometry. Preliminary data suggests that recoveries of diethylphosphate were better when the sample was extracted with ethyl acetate instead of methylene chloride. Although filtration prior to liquid-liquid extraction did not result in cleaner samples, it did improve the clarity of extracted residues. Centrifugation following derivatization produced cleaner samples without loss of the target metabolites. Future work will focus on the application of these methods for the analysis of samples collected from in vitro and in vivo studies of these compounds. Application of these methods to other matrices and other organophosphorus insecticides should also be examined.

Isolation of a Single Parameter in Ultra High Purity Electroformed Copper. CARMEN CAPETILLO (Heritage University, Toppenish, WA, 98948) ERIC HOPPE (Pacific Northwest National Laboratory, Richland, WA, 99352)

Ultra high purity electroformed copper has the potential to be used as shields and cryostats for low background germanium spectrometry due to its distinct properties such as high electrical and thermal conductivity. However; there remain traceable radioactive contaminants of thorium 232 and uranium 238 found in most samples of high purity electroformed copper. There are many factors effecting the electroformation of ultra high purity copper some of which include: current, voltage, concentration of solution, mixing, and electrical waveform. There is significant difficulty isolating a single parameter when such a wide variety of variables exist. In these experiments, changing the anode to cathode distance without affecting the overall surface area of the electrodes was critical. The plating was performed using a small cylindrical container, solution of sulfuric acid and copper sulfate, and a reverse pulse plating power supply. The copper anode material was cut into vertical columns and placed into plastic tubing which was used for a cylindrical form. This allowed the distance between the anode and cathode to change without varying the surface area of either. Other parameters such as voltage and waveform, stirring, volume and components of solution were held constant. As expected, the closer the anode was to the cathode a greater amount of copper was deposited over a shorter time period due to the lesser impedance of the reduced path length. An unanticipated outcome was that a smaller distance between the anode and cathode produced copper that had a smoother surface than that at the greater distance. Various purity assays must still be completed on the copper deposits produced. Further work must also be done to determine the optimum distance between the anode and cathode.

Investigating the Use of a Diffusion Flame to Produce Black Carbon Standards for Thermal-Optical Analysis of Carbonaceous Aerosols. DIANA ORTIZ MONTALVO (University of Puerto Rico, San Juan, PR, 931) THOMAS W. KIRCHSTETTER (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

Combustion generated particles impact climate and public health due to their ability to scatter and absorb solar radiation and alter cloud properties, and because they are small enough to be inhaled and deposit in the lungs where they may cause respiratory and other health problems. Specific concern is focused on particles that originate from the combustion of diesel fuel. Diesels particles are composed mainly of carbonaceous material, especially in locations where diesel fuel sulfur is low. Diesel particles are black due to the strongly light absorbing nature of the refractory carbon components, appropriately called black carbon (BC). This research project focuses on the uncertainty in the measurement of BC mass concentration, which is typically determined by analysis of particles collected on a filter using a thermal-optical analysis (TOA) method. Many studies have been conducted to examine the accuracy of the commonly used variations of the TOA method, which differ in their sample heating protocol, carrier gas, and optical measurement. These studies show that BC measurements are inaccurate due to the presence of organic carbon (OC) in the aerosols. OC may co-evolve with BC or char to form BC during analysis, both of which make it difficult to distinguish between the OC and BC in the sample. The goal of this study is to develop the capability of producing standard samples of known amounts of BC, either alone or mixed with other aerosol constituents, and then evaluate which TOA methods accurately determine the BC amounts. An inverted diffusion flame of methane and air was used to produce particle samples containing only BC as well as samples of BC mixed with humic acid (HA). Our study found that HA particles are light absorbing and catalyze the combustion of BC during TOA. It is expected that both of these attributes will challenge the ability of TOA methods in distinguishing between OC and BC, such as the simple two step TOA method which relies solely on temperature to distinguish between OC and BC. The samples prepared in this study were analyzed using two TOA methods to compare the estimates of BC concentration. Future work will focus on the preparation of a variety of BC standards and comparing measurements of the prepared samples using a range of TOA methods.

Kinetics Of Dissociation Of Molecular Oxygen From A Superoxorhodium Complex. MAGDALENA FURCZON (Moraine Valley Community College, Palos HIlls, IL, 60459) ANDREJA BAKAC (Ames Laboratory, Ames, IA, 50011)

Reduced transition metal complexes react with molecular oxygen to generate superoxometal species which are important in both biological and industrial oxidations with O₂. It has been shown previously that a macrocyclic cobalt complex binds oxygen only weakly and was therefore not a good candidate as a catalyst for oxidations with O₂. The goal of the current project is to determine the rate of oxygen dissociation from the rhodium analogue, which is expected to bind oxygen more strongly. The superoxorhodium complex L(H₂O)RhOO²⁺ (L = hexamethylcyclam) was prepared from O₂ and photochemically generated L(H₂O)Rh²⁺. The reverse of this reaction is homolysis, the topic of our study. After removal of free oxygen, the equilibrium is shifted to the left, and the newly generated L(H₂O)Rh²⁺ removed in a reaction with either L(H₂O)RhOO²⁺ or an externally added scavenger, such as hydrogen peroxide (H₂O₂). The kinetics of disappearance of L(H₂O)RhOO²⁺ were measured spectrophotometrically. It was found that the dissociation of O₂ from L(H₂O)RhOO²⁺ takes several hours (k_homolysis = 2 x 10-4 s-1), whereas that from L(H₂O)CoOO²⁺ requires only 100 microseconds for completion (k_homolysis = 2 x 104 s-1). The 10^8-fold difference between the two metals is outstanding and will be exploited in future work on rhodium-catalyzed oxidations with molecular oxygen. 

Linking Conductivity Measurements of Composite Heteropoly Acid Proton Exchange Membranes with Membrane Compositions and Fabrication Methods. DANA LIPFERT (Colorado School of Mines, Golden, CO, 80401) JOHN TURNER (National Renewable Energy Laboratory, Golden, CO, 89401)

Fuel cells have been proven as an efficient energy conversion device and are employed in several applications at which they have performed well. In high temperature applications (³100°C) fuel cells require a cooling and humidification system to function properly. This increases weight, size, and cost of these applications, making fuel cells impractical for them. A proton exchange membrane that functions at high temperatures will alleviate these complications and allow for mass production of fuel cells for high temperature use. Composite heteropoly acid proton exchange membranes have shown promise for high temperature use, but a chemically and mechanically stable composite membrane with sufficient conductivity has yet to be obtained. The wide variety of heteropoly acids, membrane compositions and fabrication methods allows for a plethora of composite membranes, most of which do not satisfy all requirements. The objective of this work was to associate conductivity trends with fabrication methods, conditioning methods, and weight ratios of heteropoly acids and silanes (a fixing agent for heteropoly acids). For this work 12-silicotungstic acid (12STA) and tetraethyloxosilane (TEOS) at varied weight percents were used in composite membranes fabricated by either a sol-gel solution cast method or a doctor blade film forming method. Most membranes were cured, though uncured membranes were also tested. Conductivity tests were performed at a constant cell temp of 80°C with relative humidity (RH) ranging from 50-100%. Conductivities ranged from 0.36 mS/cm to 18.7 mS/cm, the highest conductivity produced at 100% RH by a membrane with 174 weight percent (wt%) 12-STA and 56 wt% TEOS fabricated by the solution casting method. Membranes fabricated by the doctor blade method were more flexible and produced higher conductivities than membranes of the same composition fabricated with the solution casting method, which tended to be brittle. Membranes conditioned in DI water produced lower conductivities than membranes of the same composition conditioned ambiently. UV-visible absorption analysis performed on water extracts for membranes after five day soaking showed that approximately 25 wt% 12-STA were leached out of the membranes. Uncured membranes were shown to have lower conductivities than cured membranes of the same composition.

Metabolic Profiling of Carboxylic Acids and Phosphorylated Species and Using Capillary Electrophoresis-Mass Spectrometry (CE-MS). MARIJA MENTINOVA (Lawrence University, Appleton, WI, 54911) GARY J. VAN BERKEL (Oak Ridge National Laboratory, Oak Ridge, TN, 37831)

The analysis of metabolomes covers the identification and quantification of all intracellular and extracellular metabolites which exhibit molecular masses lower than 1000 Da, using a wide variety of analytical techniques. The goal of this work is to expand the analytical tool infrastructure at ORNL for analysis of plant and microbial metabolomes. A capillary electrophoresis system was coupled with an ion trap mass spectrometer. Capillary electrophoresis-mass spectrometry (CE-MS) is an ideal analytical tool for the analysis of charged species in solution. In the present work, CE-MS was applied to the separation of various candidate charged metabolites of plant metabolomes. This approach was used for the high resolution separation and sensitive detection of metabolites in the "negative ion" mass spectrometric mode. The "negative ion" mode on the mass spectrometer was used for detecting negatively charged components. Model compounds, such as small organic acids, phosphorylated carbohydrates, and adenosine phosphates, were separated and detected. For example, a three component mixture containing malic, citric and succinic acids was separated successfully using CE in its "reverse" polarity and detected by MS. In "reverse" polarity, the injection site on the CE was a high negative polarity (e.g. -20KV), and the electrospray emitter of the MS was positive relative to that (e.g. -3KV). The resulting electropherogram contained peaks with three different migration times, corresponding to each of the acids in the mixture. Similar results were obtained using the three adenosine phosphate species, as well as fructose mono- and diphosphate. These data, taken together, suggest that more complex metabolic mixtures could be separated, the individual components detected and quantified, and their metabolic profiles created. Further studies are needed to evaluate the separating power of CE-MS using more complex mixtures. This fundamental project on metabolic profiling of phosphorylated species and carboxylic acids using CE-MS is a step forward to developing a new analytical infrastructure for ORNL in metabolic analysis.

Microwave Plasma CVD Diamond Stripper Foils for the Spallation Neutron Source. AMANDA MCDERMOTT (University of Virginia, Charlottesville, VA, 22904) ROBERT W. SHAW, LESLIE L. WILSON, AND CHARLES S. FEIGERLE (Oak Ridge National Laboratory, Oak Ridge, TN, 37831)

Many accelerators use stripper foils to convert H^– to H⁺ as each pulse is injected into an accumulator ring. However, traditional carbon foils would have a short lifetime in the Spallation Neutron Source (SNS), and foil replacement requires significant beam downtime. Preliminary results suggest that diamond stripper foils could last ten times longer, or more, than carbon foils. The goal of this project is to grow foils under varying conditions for testing at the SNS to determine the best procedure to transfer to SNS technicians. Silicon substrates were patterned photolithographically, producing corrugations 5-7 µm deep around the outside edge to prevent curling of the free-standing films. The substrates were roughened in a stirred diamond-particle slurry in an ultrasonic bath to create nucleation sites. Diamond films were grown via microwave plasma assisted chemical vapor deposition (CVD) with a total flow rate of 100 standard cubic cm per minute (sccm). Nanocrystalline films were grown using 90% Ar and 1000 W microwave power at 130 torr; microcrystalline films were grown without Ar at 1300 W and 50 torr. In both cases the carbon source was 1 or 2% CH4 with H2 constituting the remaining flow. Growth temperatures varied from about 600 to 750 ºC. Scanning electron microscopy was used to determine grain size, presence of holes, and other characteristics. Finally, the Si backing was etched from acceptable foils using HF acid, leaving some Si for mounting. Films grown with CH4 concentrations between 1 and 2% were investigated as was a phenomenon consistently observed on the surface of 2% nanocrystalline films: small black spots of unknown composition. Nanocrystalline films were grown with 2% CH4 at pressures from 100 to 140 torr resulting in varied temperatures. Larger particle sizes occur in 1% nanocrystalline films than in those grown with 2% CH4, and micrographs of intermediate varieties showed that the transition in particle size is gradual. The density of black spots on 2% nanocrystalline films had a positive correlation with temperature, and a hydrogen-plasma etch procedure was developed to remove them. Foils with and without spots will be included in the next foil set for the SNS. When foil lifetimes are reported in several months, it will be possible to determine the ideal grain size and film thickness and whether removing black spots enhances performance. Examination of used foils will provide insight into failure mechanisms.

Neoteric Solvents for High Performance Liquid-Liquid Extraction. SHAYLA THOMAS (Texas Southern University, Houston, TX, 77004) SETH SNYDER (Argonne National Laboratory, Argonne, IL, 60439)

onic liquids are neoteric solvents that may play an integral role in increasing the efficiency of ethanol extraction. Since many ionic liquids may be synthesized, selecting the best one for ethanol extraction is a difficult task. Herein, we qualitatively explore and discuss physiochemical properties of ionic liquids influencing the feasibility of ethanol extraction using a functionalized hydrophobic membrane. As modeling standards for extractants, two ionic liquids, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [bmpy][Tf₂N] and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [hmim][Tf₂N], were selected. Consequently, reasonable exchange of anionic constituents and modification of cationic “R” groups of these standards resulted in the proposal of four designer ionic liquids (DILs), 1-butyl-1-methylpyrrolidinium perfluoroethyltrifluoroborate ([bmpy][CF₃CF₂BF₃]), 1-methoxyethyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([(COe)mpy][Tf₂N]), 1-hexyl-3-methylimidazolium perfluoroethyltrifluoroborate ([hmim][CF₃CF₂BF₃]), and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf₂N]), optimal for the extraction of ethanol from aqueous mixtures using a functionalized membrane in a membrane contactor. Of these, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf₂N]), was selected as the best overall DIL for complete application and processing.

New Liquid Precursors for the Deposition of Molybdenum. ROBERT PASQUARELLI (Rochester Institute of Technology, Rochester, NY, 14623) CALVIN CURTIS (National Renewable Energy Laboratory, Golden, CO, 89401)

Copper indium diselenide (CIS) solar cells have demonstrated record high efficiencies, but the technology required and number of deposition systems necessary for processing CIS solar cells makes them expensive and difficult to scale up for manufacturing. A new means of depositing molybdenum (Mo), which serves as the back contact for these devices, from liquid precursors can help lower costs and make CIS a more viable energy alternative. Deposition was studied using the organometallic precursors bis(ethylbenzene)molybdenum and tetraallyldimolybdenum dissolved in organic solvents. These solutions were deposited on glass microscope slides at temperatures between 100 and 340°C under nitrogen atmosphere. Commercial bis(ethylbenzene)molybdenum dissolved in both tetrahydrofuran and toluene was deposited on glass substrates at 200 and 340°C via spraying to produce films metallic in appearance. X-ray diffraction (XRD) showed broad peaks that could be assigned to Mo and carbonaceous contaminants (cubic Mo₂C and hexagonal ß-Mo₂C), but most of the material present appeared to be amorphous. Elemental composition should be studied in future analysis to quantify the amount of carbide and metallic Mo present. The resistivity of a sprayed film was determined using a four-point probe to be (3.23 ± 0.76) x10^-4 O-cm, a value about two orders of magnitude greater than that of pure Mo and one order of magnitude greater than the sputtered films currently used. Tetraallyldimolybdenum was synthesized under Schlenk line conditions and deposited from solution via drop coating to produce powdery films with poor adhesion. The composition of these films could not be determined using XRD given their amorphous nature. Future work will focus on removing carbide contaminants by depositing in the presence of hydrogen and producing more crystalline material.

NO2 and NO Adsorption on CeO2: a combined in situ FTIR and TPD investigation. JOHN FAIN (Sacramento City Community College, Sacramento, CA, 95822) JANUS SZANYI (Pacific Northwest National Laboratory, Richland, WA, 99352)

The NOx adsorption/desorption properties of a high surface area CeO2 (ceria) (an additive in practical lean NOx traps) was investigated using in-situ Fourier Transform Infrared Spectroscopy (FTIR) in conjunction with mass spectroscopy (MS) and temperature programmed desorption (TPD). A high surface area ceria sample, treated under various conditions (oxidation or reduction), was exposed to either NO2 or NO. NO2 adsorption experiments revealed the formation of large amounts of nitrates on ceria. These nitrate species desorbed in two stages, similarly to that we have observed previously on BaO, suggesting that these two desorption states may arise from the decomposition of surface (NO2 desorption) and bulk (NO+O2 desorption) nitrates. The amount of nitrates formed upon exposure to NO2 was higher on the oxidized samples than on the reduced ones, probably due to the consumption of some of the NO2 to fill oxygen vacancies present in the reduced samples. Furthermore, over the reduced ceria samples the formation of both N2O and N2O3 were observed in addition to the surface and bulk nitrates species. NO adsorption experiments showed limited N2 production during thermal decomposition, due to the presence of small number of defect sites (oxygen vacancies where NO can decompose), associated with the low temperature during reduction with H2 prior to NO adsorption. Keywords: NOx reduction; lean NOx traps; ceria; NO and NO2 adsorption; FTIR; TPD.

Optimization of an HPLC Method for Determination of Carbon-11 Specific Activity in [C-11] Methyl Iodide. NATALIA SHAROVA (Contra Costa College, San Pablo, CA, 94806) JAMES P. O'NEIL (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

We have created a “standard mass concentration curve” for determination very small concentrations of the methyl iodide in the carbon-11 labeled methyl iodide for further calculation of a carbon-11 specific activity. The stock solution of methyl iodide was prepared by weighing and volumetric dilution with several precautions such as sealing the vials with Teflon faced septa. This solution was then diluted with water to prepare 5 standards with the methyl iodide concentration range 3.0 – 0.03 nmoles per injection. All standards were injected in the HPLC in triplicate and the responses were analyzed by the PeakSimple data system. Collected data allowed us to create a “standard mass concentration curve” and calibrate the PeakSimple for the specific methyl iodide components. Along the experiment we came to a conclusion that standard dilutions for this experiment could be done with water; however, water as diluent had its disadvantages that limited the minimal achievable concentrations of methyl iodide and increased uncertainty of the results. In order to increase the reliability of the standard curve, the experiment should be conducted within the time period that does not exceed 12 hours, and all standard samples has to be stored in small sealed glass vials at low temperatures (˜ -5o C) while not being used.

Production of Micro- and Nanocrystalline Diamond Stripper Foils for the Spallation Neutron Source Using Microwave Plasma Chemical Vapor Deposition. DAVID POXSON (Michigan State University, East Lansing, MI, 48820) ROBERT W. SHAW (Oak Ridge National Laboratory, Oak Ridge, TN, 37831)

The Spallation Neutron Sourse(SNS) at Oak Ridge requires the use of a stripper foil to remove the electrons from its H- beam, converting it to a Proton beam (38 mA at 1 GeV). Design requirements of the SNS accumulator ring requires free standing 12mm x 20mm foils supported by a single edge with an areal density of ~350 g/cm2 (~1.0 m thick). Traditionally, stripper foils made of evaporated carbon have been used in similar applications at lower power. However beam simulations have predicted that diamond foils will provide a longer lifetime, decreasing the frequency of foil replacement in a radioactive environment and increasing beam up-time. In order to achieve diamond growth on a silicon substrate, the surface was pre-treated with a scratching slurry of 1:1 0.3 grams 600 grit, <0.25 ?m diamond powder and 60 ml of methanol in an ultrasonic bath. This step of nucleation "seeding" is critical in achieving a uniform growth, free from pinholes or irregular crystal sizes. An improvement to the seeding procedure has been made with the addition of a continuous stirring mechanism. With constant mixing, films grow more uniformly, with fewer pinholes and similar defects. To create a structurally rigid, free standing foil, a photolithography technique was used to pattern ~6 ?m deep U-shaped corrugations into the substrate. Foils were produced using Microwave Plasma Chemical Vapor Deposition (MPCVD) onto silicon. Microcrystalline foils were successfully grown at 1300 Watts, 50 Torr, 2% CH4, 98% H2, for ~110 minutes. Upon removal from the substrate however, structural stress across the foil induced enough torque that ~50% of the foils tore themselves apart and none remained entirely flat. Structurally superior nanocrystalline foils were grown at 1000 Watts, 130 Torr, 1%-2% CH4, 8%-9% H2 90% Ar. Nanocrystalline foils had a higher survival rate and remained flat after removal from the substrate. Additionally, nanocrystalline films have shown fewer pinholes and decreased surface roughness. It has been shown that thicker foils achieve a higher stripping efficiency. A 1% carbon nanocrystalline ~250 ?g/cm2 sample sent to The Los Alamos Proton Storage Ring was successfully used for three months. Two more 2% carbon nanogrowths of ~280 ?g/cm2 were prepared and sent to Los Alamos for future testing and use. Subsequent work will consist of modifying the pretreatment and growth conditions to ensure uniform thickness of the films.

Protonation of Molybdenum Cyclopentadienyl Phosphino Chloride Complexes with Triflic Acid. SHARON LEE (University of California, Berkeley, Berkeley, CA, 94720) R. MORRIS BULLOCK (Brookhaven National Laboratory, Upton, NY, 11973)

The conversion of ketones to alcohols has a major impact on pharmaceutical chemistry due to its application in the synthesis of drugs. Current methods require expensive transition metal catalysts based on rhodium or ruthenium. Harsh reagents such as LiAlH₄ and NaBH₄ require stoichiometric amounts and produce significant amounts of waste. Therefore, interest in catalytic molybdenum compounds that exhibit this reactivity has been growing. To be effective in an ionic hydrogenation mechanism, such molybdenum compounds must have the ability to protonate as well as transfer a hydride to a ketone to form an alcohol. This paper introduces molybdenum compounds made through the addition of triflic acid (HOTf = HOSO₂CF₃) in dichloromethane to synthesized Cp(CO)(Ph₂PRPPh₂)MoCl (R = CH₂, (CH₂)₃