Raman spectroscopy has recently become a common laboratory analytical technique due to the introduction of technology such as lasers, charge-coupled devices, and holographic filters. The information given by Raman spectroscopy is complimentary to infrared absorption spectroscopy, but sample preparation is often much easier, if any is needed at all. Because of this, the field of Raman spectroscopy has expanded in many areas, including mineralogy. The ongoing development of a database of Raman spectra of minerals enables facile identification of many minerals. Pyroxenes are a class of minerals that make up approximately 25% of the Earth's upper mantle, to a depth of 400 km. A recently discovered phase change in pyroxenes, accompanied by a volume change, is now accepted as the origin of some deep-focus earthquakes, which are clustered at a depth of approximately 225 km. However, the bonding change that accompanies this phase change is not completely understood. Raman spectroscopy was utilized to follow the phase change of spodumene. Polarized spectra of an oriented single crystal of spodumene were utilized to assign Raman modes that were previously ambiguously assigned in the pyroxenes. The pressure-induced phase transition was also followed in LiFeSi2O6 utilizing both Raman spectroscopy and single crystal x-ray diffraction. Similarities were noted between the Raman spectra of spodumene and LiFeSi2O6, enabling the assignment of Raman bands in the second material studied. Finally, a third pyroxene, LiCrSi2O6, was studied with Raman spectroscopy while the sample was subjected to pressure. This material changed color with application of pressure and the color change was quantified with visible absorption spectroscopy. Though no phase change occurred in this material, changes in the spectra did occur at high pressures. These high-pressure changes in the Raman spectra were observed in all three crystals studied and could provide a better understanding of the pyroxenes at high pressures. Additionally, none of the three pyroxenes in P21/c phase displayed a doublet of peaks in the spectroscopic region that had been previously utilized as a benchmark for the identification of the P21/c phase of the pyroxenes until higher pressures. Spodumene did not display a doublet at any pressure studied.

Imaging spectroscopy combines the spatial discrimination of imaging techniques with the chemical information of spectroscopy to form a powerful tool for the study of chemically heterogeneous systems. This work describes the in situ qualitative and quantitative analysis of contaminant transport flow cells and of high-performance thin-layer chromatography (HPTLC) plates by near-infrared imaging spectroscopy. A solid-state, near-infrared imaging spectrometer was constructed for these studies. The spectrometer utilized an imaging quality acousto-optic tunable filter for wavelength selection over the 1.3-2.3 μ range and a cryogenically cooled, 240 x 324 pixel platinum silicide camera for detection. Samples were analyzed by either diffuse reflectance or diffuse transmittance using a 250 W quartz-tungsten-halogen lamp for sample illumination. The first series of investigations focused on the analysis of laboratory-scale flow cells, which are used to study the transport of non-aqueous phase liquid (NAPL) contaminants in the soil and groundwater. Current detection systems used for determining NAPL distribution are incapable of distinguishing between chemical components in NAPL mixtures, limiting flow cell experiments to the study of simple systems. This research utilized the near-infrared imaging spectrometer and multivariate calibration techniques to quantitatively determine the concentrations of individual constituents in binary NAPL mixtures within vadose zone and aquifer models. The vadose zone calibration data was used to determine the spatial distribution of each NAPL constituent in situ during a dynamic, multi-component flow cell experiment that modeled the remediation of NAPL contaminated soil. This technique, the first to quantitatively determine the in situ distribution of the individual NAPL phase constituents, represents the state of the art in detection for contaminant transport flow cells. The second series of investigations focused on analysis of samples on HPTLC plates. Conventional systems require visualization techniques to detect compounds lacking a chromophore or fluorophore. This research utilized the near-infrared imaging spectrometer as a non-destructive detection technique to provide qualitative and quantitative information for caffeine samples on HPTLC plates. Both diffuse reflectance and diffuse transmittance measurements provided detection limits of several micrograms. The caffeine spectrum was clearly distinguishable down to 25 μg using a diffuse reflectance geometry with a mirrored backing applied to the HPTLC plate.

A broadband, multichannel, single mode, planar waveguide based ATR spectrometer was developed. A sensitivity enhancement of three orders of magnitude compared to the conventional transmission spectroscopic technique has been experimentally achieved. Applications to protein submonolayers adsorbed on glass surfaces provided the first results on the spectral characterization of those molecular films. The increased information content and the higher sensitivity response allowed us to experimentally determine the molecular orientation of organic films over a broad spectral range. The work developed here is a research tool that allows the investigation of some fundamental problems of molecular assemblies and a platform to develop new technological devices of high sensitivity and selectivity, such as biosensors.

This work describes the construction of an inductively-coupled plasma tandem quadrupole mass spectrometer where a quadrupole ion storage trap acts as a second sector and collision cell to achieve neutralization or collisional dissociation of interfering species before mass analysis. Because most elements exist as singly-charged ions in an inductively-coupled plasma (ICP) plume, the ICP can be used as an ionization source for mass analysis (ICP/MS). By reducing the sample to elemental ions before mass analysis, ICP/MS spectra tend to be simple compared with those obtained by ICP-optical emission spectrometry (ICP-OES) where elements may have hundreds to thousands of emission lines and spectral overlaps can be severe. This is especially troublesome in the analysis of rare earth elements which have the largest numbers of active emission lines when excited in an ICP. In addition, detection limits by ICP/MS are often up to 3 orders of magnitude lower than by ICP-OES. ICP/MS analysis is not immune from isobaric and isotopic interferences or matrix effects. For most analyses, an acid digestion precedes aspiration as an aqueous solution into an argon plasma gas. This can lead to large amounts of Ar+ etc., which may interfere to varying degrees with analytes of interest. Oxides, argides and hydrides of matrix ions or other analytes may also form and interfere. These same processes can also split peak areas between the atomic form of an analyte and the molecular. In isotope ratio studies where precise measurements on more than one isotope per analyte are needed, these effects may be compounded. Isobaric interferences normally require high resolution mass analysis to resolve if they cannot be separated prior to sample introduction. However, the interface between a high vacuum, high resolution sector or ion cyclotron resonance mass spectrometer and an atmospheric pressure plasma is non-trivial and such instruments are expensive. The focus of this work is new approach which uses a collision cell where weakly-bound molecular species can be dissociated and ions with relatively high electron affinities, such as Ar+, can be neutralized through charge exchange reactions.

Organochlorine compounds, such as polychlorinated biphenyls (PCBs), pentachlorophenol (PCP), p,p'-DDE and Toxaphene, have been widely used in industry and agriculture for more than fifty years. Although they have served their purpose very effectively and at low cost, many of these compounds have been banned in the United States due to their persistence in the environment and their threat to human health. Their natural resistance to degradation has made organochlorine compounds the target of many studies that have been designed to convert them into less toxic compounds. At present there is not a single, simple method than can completely dechlorinate PCBs, PCP, p,p'-DDE and Toxaphene. The work presented here reports the use of a novel bimetallic system, palladized iron (Pd/Fe), to effect the complete dechlorination of these compounds, at ambient temperature and pressure, in a matter of minutes. The dechlorination reaction occurs on the surface of the palladized iron, with removal of all the chlorine atoms from the chlorinated compound and yields the completely dechlorinated molecule and chloride ions as reaction products. The chlorinated compound is reductively dechlorinated while the iron particles are oxidized to Fe²⁺ Water is also reduced in the presence of iron, generating hydrogen, which is collected in the palladium lattice. The palladium is therefore necessary to store hydrogen gas; the "Pd·H₂" acts as a powerful reducing agent and is primarily responsible for the rapid and complete dechlorination of the organochlorine compounds. The Pd/Fe bimetallic system is potentially useful for the large scale remediation of groundwater or soil contaminated with organochlorine compounds. Palladized iron is relatively inexpensive and easy to prepare, and it rapidly and completely dechlorinates organochlorine compounds. For these reasons, the Pd/Fe system should be investigated further for applications in the field.

Understanding and controlling protein adsorption is fundamentally important to the successful development of synthetic biomaterials and implantable chemical sensing devices. However, the study of protein adsorption, and in particular, orientation in protein thin films has been hampered by inadequate methods with which to study weakly absorbing thin protein films. In this work, Integrated Optical Waveguide-Attenuated Total Reflection Linear Dichroism (IOW-ATR LD) coupled with fluorescence emission anisotropy was used to study: (1) the orientation of Mb as a function of the adsorbent surface and surface coverage, and (2) the orientation distributions of cyt c adsorbed to various surfaces. It was found that the average molecular orientation of an adsorbed protein film: (1) is dependent on the chemical and/or physical characteristics of the adsorbent surface, and (2) is dependent on the protein surface coverage. It was also determined that the macroscopic order of an adsorbed protein film is dependent on the number of different types of protein-surface interactions in a given system. If there is one dominant type of interaction between the between the protein and the surface which is limited to a specific region on the surface of the protein, an ordered protein film will be produced. However, as the number of the type of protein-surface interactions increases, the distribution of orientations also increases, leading to a disordered film. Finally, a broadband waveguide coupling device has been developed which allows spectroscopic measurements of submonolayer to monolayer surface coverages of proteins to be performed.

New biomaterials for permanent cardiac pacemaking electrode applications based on Au surfaces chemically modified with self-assembled monolayers (SAMs) have been developed. The research described herein focuses on four areas related to understanding the extraordinary pacing exhibited by modified pacemaker electrodes. SAM-modified pacemaker electrodes were fabricated and tested in canines for chronic and acute cardiac pacing. In addition to having electrical properties suitable for pacing the heart, SAM-modified electrodes are proven superior to control electrodes in pacing performance. The data suggest that the biocompatibility of electrically conductive materials can be controlled at the molecular level with monolayer organic surface films. The development of a small rodent model for studying cardiac pacing was explored as an alternative to using canines in clinical studies. Rodents, not previously used for such studies, were demonstrated to be excellent mammals for testing initial electrode modification strategies. Myocardial tissue resistance in a living mammalian heart was determined using chronoamperometry and cyclic voltammetry of Ru(NH3 Pacemaker systems represent complete electrochemical cells. Thus, modified pacemaker electrodes are simply examples of chemically modified electrodes, an area of electrochemistry which has been studied extensively over the past two decades. For these types of systems, the interfacial chemistry occurring in the vicinity of the SAM is crucial to its function. Therefore, investigations into the stability, order, and orientation of SAMs at the metal electrode surface, and solvent behavior at the outer edge of the SAMs were undertaken. Such fundamental information is critical in understanding the biocompatibility of these modified pacemaker electrodes, and potentially, in understanding the mechanism for the pacing efficacy of the electrode modification. Surface Raman spectroscopy using an emersion approach was developed as an exceptional technique for probing the structural order and stability of SAMs on Ag and Au after exposure to solvent, electrolyte, and potential. Finally, the stability of these SAM-modified pacemaker electrodes to air and mechanical stress was investigated. Raman spectroscopy, cyclic voltammetry and x-ray photoelectron spectroscopy were utilized to better understand the shelf-life of modified electrodes.

Every day, billions of senescent human erythrocytes are removed from the circulation. The mechanism of recognition involves the formation of a neo-antigen on senescent cells, which binds autologous immunoglobulin and targets the senescent cell for phagocytosis. This neo-antigen is derived from an existing integral membrane protein, band 3. The molecular mechanisms underlying the formation of this neo-antigen during the aging process are poorly understood, but oxidative damage is suggested to be a critical event. Several post-translational modifications have been associated with aging that may contribute to altered antigenicity of the band 3 molecule, either directly by forming a covalent modification that contributes to the neo-antigen epitope or indirectly by altering the conformation of the protein, exposing hidden epitopes. Tandem mass spectral analysis was performed on tryptic digests of the band 3 protein from young and old erythrocytes. Six oxidations of methionyl residues were detected, one of which lies adjacent to a region of band 3 proposed to form an epitope of the neo-antigen and one of which lies between proposed antigenic regions. Studies of vitamin E deficiency and supplementation strongly support oxidation as a pivotal event in alteration of band 3 with aging, and the oxidized methionines identified in this study may represent the critical sites of damage. A possible deamidation was also identified in an antigenic region of band 3. Deamidation is suggested to serve as a molecular timeclock for proteins, and conversion of a glutamine to a glutamic acid may alter the antigenicity at this critical region of band 3. This work represents the first application of tandem MS/MS methodologies to a large integral membrane protein. Forty-four of the 75 band 3 tryptic peptides were characterized, covering 61% of the band 3 polypeptide. Many of the tryptic peptides did not meet criteria for proper peptide analysis. Of the remaining peptides, 95.3% of the band 3 molecule was characterized, with 55% sequenced by MS/MS. Since only partial sequence information is expected for this type of analysis, these percentages represent a tremendously successful application of the technique.

The accuracy and precision of catalytic converter analysis using conventional analytical methodology such as fire assay, x-ray fluorescence, atomic absorption and ICP-AES are typically in the range of ±7-10% RSD. Due to the high cost of noble metals, methods of analysis with increased accuracy and precision are desired to evaluate the loading of noble metals onto converter bricks. The investigations described in this work have resulted in a better understanding of many of the inherent problems and have contributed new approaches for sample dissolution and analysis using array detector based Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). These methods are shown to be accurate and precise for the analysis of Pt, Pd, and Rh in catalytic converters. Catalytic converters are difficult to dissolve by conventional acid methodology. While carius, tubes have previously been employed to dissolve small weights of sample, complete dissolution of increased amounts of sample, as needed for high precision ICP-AES analysis, has been hindered by the insufficient oxidation potential of the acids in the carius tube. In this work, the addition of ferric chloride is shown to increase the dissolving power of the carius tube method and specifically targets Pt, Pd and Rh for dissolution. Simultaneous collection of analyte wavelengths and simultaneous background correction, as performed with multichannel array detector ICP-AES instrumentation, have enhanced sensitivity and precision in catalytic converter analysis when compared to single channel instrumentation. The studies described within this dissertation demonstrate that flicker noise has been effectively eliminated through the use of multichannel array based ICP-AES instrumentation. With proper line selection and the use of the high-resolution system, Pt, Pd and Rh in catalytic converters can be analyzed with precision of 1-1.5%. ICP-AES accuracy has been confirmed through isotope dilution ICP-MS employing new methodology to avoid Zr isobaric interferences.

The research which will be presented on the combination of Raman spectroscopy with an ultrahigh vacuum (UHV) environment. The data show that UHV Raman spectroscopy is a useful analytical technique for modeling electrochemical interfaces. Raman spectroscopy and x-ray photoelectron spectroscopy (XPS) were utilized to study the surface chemistry of 1-butanol and thiophenol. These molecules were studied on coldly-deposited and annealed Ag films grown in the UHV environment. Surface Raman studies of molecules adsorbed on coldly-deposited Ag films are abundant, because these films support significant surface Raman enhancement. However, recent advances in instrumentation make studies at relatively unenhancing annealed Ag films possible. Roughness and surface enhancement factors for coldly-deposited and annealed Ag surfaces were investigated using thiophenol. In addition, a correction factor was determined which allows data acquired in the UHV environment to be directly compared to data acquired in the laboratory ambient. Butanol orientation was studied at these Ag surfaces using Raman surface selection rules. The orientation of butanol is dictated by the solid-vacuum interface and the unique surface morphology present at these surfaces. Br and Na ions were used to model the interaction of butanol with electrolyte species found in normal electrochemical systems. The coverages of Br and Na were calibrated using XPS. The orientation of butanol was determined for varying coverages of these ions and compared the bare Ag surfaces. My research represents the first stages of modeling the electrochemical double-layer in the UHV environment using Raman spectroscopy.