Source: Dissertation Abstracts International, Volume: 27-11, Section: B, page: 3805. / Thesis (Ph.D.)--The Florida State University, 1966.

Photo-diode array provides a variety of options to reveal the presence of more than a single substance in a peak. The commonly used approaches are checking the ratio of absorbance at two wavelengths, spectral similarity at upslope and downslope positions, derivative of chromatograms, and variation of time profile maximum at different wavelengths. But the reliability of these methods is affected by small resolution, spectral similarity, drift, and signal to noise ratio. A method of detecting overlapped peaks based on multi-variate analysis of data of LC/UV-Vis diode array detector has been developed to determine the peak purity. It is not required to have an assumption of the peak shape of the chromatogram or spectra of individual components. Pseudo tailing and real tailing elution can be identified easily. / The Raman spectra of the pure crystalline phase and pure amorphous are now well characterized. However, the experimental determination of the Raman spectrum of the interface has been elusive because of the impossibility of having a structure made of these characteristics. A deconvolution by factor analysis of the Raman spectra in the internal mode region of different linear polyethylene covering a wide range of crystallinity content is used in this work in order to generate the Raman spectrum of the interface of a polymeric crystal. / A major hurdle to the rapid development of conductive polymers is the lack of knowledge of the relationship between structure and physical and chemical properties. The analysis of polypyrrole is limited by its insolubility, lack of processability, and opacity. Raman spectroscopy has proved to be an effective technique in measuring opaque or turbid samples whereas conventional IR and UV methods are restricted. In situ Raman scattering has been used to follow the kinetics of the heterogeneous oxidative chemical polymerization of pyrrole. The recently developed fiber optics techniques provide a convenient and flexible approach to in-situ monitoring and circumvent the limitations of experimental conditions such as distance, vibration, size, and temperature. / Source: Dissertation Abstracts International, Volume: 52-12, Section: B, page: 6357. / Major Professor: Charles K. Mann. / Thesis (Ph.D.)--The Florida State University, 1991.

The work deals with the incorporation of multivariate computational methods in chemical analysis to allow signal and resolution enhancement. Examples are taken from four analytical techniques, Raman spectroscopy, nuclear magnetic resonance spectroscopy, gas chromatography, and infrared spectroscopy. A general discussion of the multivariate methods that are used is presented in Chapter I. These are correlation, least-squares fitting, and abstract factor analysis. / In chapter II, the feasibility of quantitative resonance Raman spectroscopy with an excimer laser as light source is discussed. To compensate for instrument uncertainty, it is necessary to use an internal standard. In this application, the sharp absorption peaks of the compounds studied make the application of a conventional internal standard particularly difficult because of self reversal. This problem is overcome by the use of least squares fitting to resolve and quantify the overlapped analyte and internal standard bands. / A discussion of signal enhancement in gas chromatography is given in Chapter III. The problems of resolution of heavily overlapped peaks and of quantification of peaks which occur on a shifting baseline are addressed. Simulated data sets are used to investigate the scope of applicability of the computational methods that are used. / Chapter IV discusses the suitability of abstract factor analysis for extraction of information from a set of spectra produced by solid state ('13)C NMR measurements, using the technique of dipolar dephasing. A model compound, glycine, is used in this examination. An organic rich marine sediment sample is analyzed to reveal the applicability of this technique to other interesting systems. / In Chapter V, correlation and least squares fitting are utilized to determine molybdenum trifluorophosphine carbonyl complex mixtures by infrared spectroscopy for the study of scrambling substitution reaction of metal complexes. Results of a series of measurements made on known mixtures are first discussed. The method is then applied to mixtures that were produced by photochemical reactions. Results are compared with those obtained by gas chromatographic measurements. Values of thermal equilibrium constants from both techniques are presented. The degree of scrambling substitutions of the ligands PF(,3) and CO are discussed. / Source: Dissertation Abstracts International, Volume: 48-03, Section: B, page: 0731. / Thesis (Ph.D.)--The Florida State University, 1987.

Three liquid chromatography bonded stationary phases--amino-, diol- and cyano-silica--have been characterized by two different methods. In the first, the retention of polar solutes in binary mixtures of hexane and polar solvents by the three bonded phases was studied as a function of the selectivity of both solutes and solvents. Three solutes and three solvents were chosen from the apices of the Snyder Selectivity Triangle. Fitting of this retention data to the Snyder adsorption-displacement model generated a three-by-three matrix of data and complete data sets for each bonded phase. It was demonstrated that these matrices not only provide practical retention information, but also give insight into the mechanism responsible for observed behavior. / The second approach utilized the relationship between experimentally generated solvent strengths and bonded phase solubility parameters. These parameters were used to position the three bonded phases on the selectivity triangle. / An important result to emerge from both studies is the necessity for characterizing solute/solvent/bonded phase combinations. A bonded phase simply cannot be characterized apart from the solute and solvent. / Source: Dissertation Abstracts International, Volume: 48-03, Section: B, page: 0733. / Thesis (Ph.D.)--The Florida State University, 1987.

The proton transfer dynamics of 3-hydroxyflavone (3-HF) and lumcihrome were investigated using picosecond time-resolved spectroscopy. The excited-state proton transfer of 3-HF exhibited a very rapid, single exponential risetime of the tautomer species in very pure hydrocarbon solvents. A slight temperature dependence was observed: a risetime less than 10 ps at room temperature increasing to ca. 40 ps at 77K. / The ground-state proton transfer of 3-HF was investigated using transient absorption spectroscopy. Stimulated emission pumping (SEP) was used to induce a significant, ground-state tautomer population. Two absorption profile series, without and with SEP, exhibited identical absorption bands. The rise and decay of the absorption bands mimicked the known rise and decay of the tautomer emission, and were therefore, attributed to absorption by the excited-state tautomer. The rate of the ground-state proton transfer was inferred to be less than 30 ps, the time required for the SEP process, since no different absorption profile was observed in the two different, absorption series. / The excited-state proton transfer of lumichrome in two different solvent systems was investigated. In varying concentrations of pyridine in p-dioxane, lumichrome exhibited two different rates of proton transfer inferred from two risetimes of the tautomer species. In both cases, a pyridinium cation transported the proton. The two rates resulted from different orientations of the pyridine in the lumichrome-pyridine, ground-state complexes. / Acetic acid in ethanol comprised the second solvent system in which the excited-state, proton-transfer of lumichrome was investigated. In this solvent system, three different rates of proton transfer were detected. Two different rates were inferred from a biexponential decay of the normal fluorescence. From a more rapid, tautomer risetime, faster than 10 ps, the remaining, third rate of proton transfer was deduced. While the acetic acid, doubly hydrogen bonded to the lumichrome, promotes the proton transfer, different acetic acid-lumichrome, ground-state complexes were responsible for the different rates of proton transfer. / Source: Dissertation Abstracts International, Volume: 47-12, Section: B, page: 4846. / Thesis (Ph.D.)--The Florida State University, 1986.

This report describes a series of studies carried out as part of an effort to develop simple and rugged methods for on-line monitoring based on Raman spectroscopy. A comparison of sensitivity for Raman and infrared measurements shows the Raman approach has a substantial advantage over infrared measurements for direct multicomponent analyses. The infrared results are strongly influenced by the presence of concomitants, even for the simple two component system employed in this study. Various fiber optic probe systems are considered and compared. A bifurcated optical fiber bundle system is developed for exciting and collecting Raman scattering. The criteria for the optical design and the properties of the system are discussed. Raman spectra obtained with this system are much less subject to interference of background emission from silica than single fiber systems that are investigated. Resonance enhanced Raman spectroscopy offers a considerable sensitivity advantage over normal Raman spectroscopy, and the utility of this approach for on-line monitoring is examined. It is a selective and sensitive technique which provides structural information on a molecule, but its utility for quantitative analysis is obscured by sample absorption. A correction method for absorption in resonance Raman measurements for the fiber system is presented. Measurements on solutions of a strongly absorbing azo dye have been used to test the approach. A quantitative continuous flow analysis is demonstrated by coupling the system with a liquid chromatograph. A chromatographically unresolved azo dye mixture is resolved in the spectral dimension. Individual chromatograms are then generated, and the limits of detection for the azo dyes are about 160 ng. / Source: Dissertation Abstracts International, Volume: 52-06, Section: B, page: 3027. / Major Professor: Thomas J. Vickers. / Thesis (Ph.D.)--The Florida State University, 1991.

The well developed poly(sulfonium salt) precursor route to poly(arylene vinylenes) (PAV's) has made the PAV family one of the most promising classes of conducting polymers in view of future applications such as electronic devices and electroluminescent materials. The objectives of this dissertation have been to understand (i) the role played by counterions in the polyelectrolyte upon thermal conversion to its fully conjugated polymer, (ii) the doping mechanism and doping induced chemical modification, and (iii) both surface and bulk chemical modification on PAV's. / Poly(sulfonium salt) precursors containing fluoride, chloride, bromide, and acetate were prepared by ion-exchange dialysis of the chloride polyelectrolyte. Thermal gravimetric analysis (TGA) revealed that a much higher temperature, $ca.\ 350\sp\circ$C, was necessary to convert acetate precursor to PPV whereas bromide precursor eliminated at the lowest temperature, $ca.\ 200\sp\circ$C. Infrared spectra suggested that acetate became covalently bound to the polymer backbone rather than forming an ion-pair as in other cases. In situ conductivity measurements on $\rm H\sb2SO\sb4$-doped PPV's showed a marked difference on the limiting conductivity for PPV prepared by different precursors. TG-IR (TGA coupled to infrared) analysis indicated that the products of thermal elimination involved tetrahydrothiophene, the conjugated acid of the anion, and water and implied a different elimination mechanism depending on the anion at various temperature. / Various doping agents, i.e., $\rm H\sb2SO\sb4,\ Fe(ClO\sb4)\sb3{\cdot}6H\sb2O$, and FeCl$\sb3$, were used to dope PPV. IR spectra revealed that irreversible chemical modifications occurred in all cases, i.e., sulfonation, carbonylation, and chlorination. These functional groups were identified by appropriate chemical derivatization, IR, UV-Vis, and ESCA spectroscopies and elemental analysis. Regeneration of modified PPV's via desulfonation and dehydrochlorination has been investigated. A different doping mechanism than the published one has been proposed in the case of $\rm H\sb2SO\sb4$-doping. / Graft copolymerization of various monomers, e.g., iso-butyl vinyl ether (i-BVE), vinyl anisole (VA), and N-vinyl carbazole (N-VC), onto PPV surfaces by means of cationic initiated polymerization has been investigated. Both poly(i-BVE) and poly(VA) were successfully grafted on PPV as confirmed by extensive wash with various solvents and by IR spectroscopy. However, poly(N-VC) was found only in solution. / Demethylation of poly(2,5-dimethoxy-1,4-phenylene vinylene) (PDMPV) using BBr$\sb3$ has been studied. Surface demethylation can be achieved by choosing an appropriate reaction solvent. Functional groups such as ester and urethane linkages have been transferred to PDMPV films through the "OH" handle produced by demethylation. Derivatives were characterized by IR spectroscopy. / Source: Dissertation Abstracts International, Volume: 56-04, Section: B, page: 1985. / Major Professor: Joseph B. Schlenoff. / Thesis (Ph.D.)--The Florida State University, 1994.

Source: Dissertation Abstracts International, Volume: 30-02, Section: B, page: 0535. / Thesis (Ph.D.)--The Florida State University, 1968.

No description available.

No description available.