The electrochemical behavior of the four arsenic species, As(III), As(V), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA), was examined at a gold disk electrode. The As(III) species in solution was determined by anodic stripping voltammetry. The experimental conditions that were established for this determination were employed for the determination of As(III) that was formed by the reduction of As(V) by glutathione. The presence of an Arsenic(III)-glutathione complex in solution was established by cyclic voltammetry.

The electrochemical behavior of L-cysteine, 3-mercaptopropionic acid, dimercaptopropanesulfonic acid and dimercaptosuccinic acid, was examined at a mercury film electrode, gold electrode and platinum electrode. The effect of scan rate, pH and concentration were determined by cyclic voltammetry. The comparison of the cyclic voltammograms, established a great similarity among the monomercapto compounds at different molecular weight and structure and among the dimercapto compounds that were studied. Differences between the behavior of dimercapto and monomercapto compounds were also established. The cyclic voltammetry of arsenic is affected by the presence of cysteine, and the formation of an arsenic-cysteine complex is established by the shift of the oxidation potential of elemental arsenic at a gold electrode.

Source: Dissertation Abstracts International, Volume: 41-07, Section: B, page: 2599. / Thesis (Ph.D.)--The Florida State University, 1980.

Three new, glow discharge devices have been designed and investigated. The new devices were made to improve the measurement precision of solution residues. An improvement in the precision would allow the glow discharge to be more fully exploited as an excitation source. / The first device constructed operated at atmospheric pressure. Detection limits are reported for Cu, Na, Sr, and In. / The second device described is a low pressure device for discrete samples. The detection limits for Cu, V, In, and Co are comparable to those obtained with demountable hollow cathode lamps, but with better precision. Rotational and excitation temperatures are examined as functions of fill gas pressure and discharge current. A sputtering constant is presented and the technique for measuring this parameter is described. / The third device described provides continuous sample introduction into a low pressure glow discharge. A chain conveyor is used for sample transport. Results are reported for aqueous Pb, Cd, B, and Cu sample solutions. Studies of sample volatility, matrix, and organic solvent effects are reported. The device is shown to possess many useful features. Its potential utility as an element selective detector for liquid chromatography is suggested. / Source: Dissertation Abstracts International, Volume: 43-09, Section: B, page: 2889. / Thesis (Ph.D.)--The Florida State University, 1982.

Raman spectroscopy has been demonstrated to be a convenient tool for the elucidation of molecular structure and quantitative analysis of chemical compounds. Some intrinsic disadvantages of this technique restrict its use only to research facilities. The goal of this research is to develop methods to minimize these disadvantages and prove that Raman spectroscopy can be widely used in industrial applications. A simple device along with fiber optics is used in a dispersive Raman system to show the reproducibility of measurements of solid samples without an internal standard. Changes in Raman features due to temperature changes are examined and discussed in this report. A wavelength calibration routine is developed for multichannel detectors which allows the errors for the estimation of line positions in a spectrum to be less than 0.5 A. The Hadamard transform technique is used to measure chemical agent simulants on metal surface and offers an improvement in the limit of detection for the quantitative analysis of Raman measurements. A diode laser Raman system composed of a compact diode laser source, a dispersive spectrograph, and fiber optics is established and tested. The stability of the excitation wavelength is improved by using a fiber bundle with a larger core diameter. Three filters are also compared for their Rayleigh line rejection efficiency. Chemical agent simulants are also measured with the diode laser system to test the possibility of building a field monitoring Raman system. In order to measure samples of small amount, surface-enhanced Raman spectroscopy (SERS) is also investigated in this research. Quantitative analysis with this technique is difficult by directly using enhanced Raman spectra, but the kinetic phenomenon of SERS exhibits the possibility of sample quantitation. To illustrate the application of Raman spectroscopy in the polymer / industry, samples of fire-retardant in nylon are successfully analyzed with the FT-Raman system for the determination of homogeneity and amount of fire-retardant in samples. / Source: Dissertation Abstracts International, Volume: 55-04, Section: B, page: 1411. / Major Professor: Thomas J. Vickers. / Thesis (Ph.D.)--The Florida State University, 1994.

In micellar liquid chromatography, interactions of the surfactants with the surface of chemically derivatized stationary phases are important. To fully understand the chemical environment of surfactant-modified stationary phases, solid state $\sp{13}$C NMR techniques, including Cross Polarization (CP), Magic Angle Spinning (MAS), and high power proton decoupling, have been used to study the interactions of three surfactants with octadecyl (C$\sb{18}),$ octyl (C$\sb8)$ and cyanopropyl (cyano) chemically derivatized silica gels. The three surfactants studied, cetyltrimethylammonium bromide (CTAB), dodecyltrimethylammonium bromide (DTAB) and sodium dodecylsulfate (SDS), are commonly used in micellar reversed phase liquid chromatography (RPLC). The selectivity, retention and efficiency of these three surfactants were evaluated through the chromatographic behavior of a set of vanillin test compounds. / The motional behavior of surfactant-modified stationary phases were characterized by $\sp{13}$C NMR polarization transfer rates and relaxation mechanisms. The efficiency of polarization transfer is represented by the T$\sb{\rm CH}$ time constant, and relaxation mechanisms by the $\sp{13}$C T$\sb{1\rho}$ relaxation parameter. The T$\sb{\rm CH}$ time constant and the $\sp{13}$C T$\sb{1\rho}$ relaxation parameter were obtained for both pure and adsorbed surfactants, and for the pure cyano stationary phase. / Both the chromatographic results and the $\sp{13}$C NMR data suggest that differences in selectivity, retention and efficiency among SDS, CTAB and DTAB-modified stationary phases are due to the differing nature of each surfactant-bonded phase association. Models of SDS, CTAB and DTAB adsorbed on C$\sb{18}$ and C$\sb8$ have been proposed based on two sets of data: chromatographic selectivity, retention and efficiency; and rigidity of surfactant-modified stationary phases indicated by the T$\sb{\rm CH}$ time constants and $\sp{13}$C T$\sb{1\rho}$ relaxation parameters. The adsorption behavior of SDS, CTAB and DTAB onto the cyano phase was also analyzed by direct observation of the T$\sb{\rm CH}$ time constant and $\sp{13}$C T$\sb{1\rho}$ relaxation parameter of cyano functional group. / Source: Dissertation Abstracts International, Volume: 54-03, Section: B, page: 1371. / Major Professor: William T. Cooper. / Thesis (Ph.D.)--The Florida State University, 1993.

The research presented in this dissertation is aimed at the characterization of normal bonded phases and the identification of important retention mechanism. First, three solutes and three solvents are chosen to represent the apices of the Snyder triangle, where each apex represents a solute or solvent whose primary interaction is either dipolar, proton accepting or proton donating. Thus, the retention information from each solute-solvent pari is unique and important retention mechanisms can be readily identified. Second, system peaks are used to characterize retention in the amino normal-bonded phase. One important result from this study is that when normal-bonded phase columns are used with high modifier concentrations, the partition model seems to be more appropriate in interpreting the retention data. Multidimensional separation procedures become especially important for complex samples consisting of numerous components. For such samples linear columns generally have inadequate power for cleanly resolving the components present, and this failure becomes increasingly pronounced as the number of components increases. Due to the unique characteristics of normal-bonded phase columns, serial coupling of any two of them seems to provide truly multidimensional separations. / Source: Dissertation Abstracts International, Volume: 53-11, Section: B, page: 5681. / Major Professor: William T. Cooper, III. / Thesis (Ph.D.)--The Florida State University, 1992.

The oxidation state distribution of plutonium in seawater, pore water from marine sediments, and a series of model solutions similar to seawater was measured using a TTA solvent extraction technique and alpha liquid scintillation counting methods. Electromigration was used to compare migration behavior of americium in 0.7M NaCl solutions (pH 6.5 to 8.0) with the behavior calculated from predicted speciation. / In all pH 8 solutions studied, Pu(VI) was rapidly reduced to Pu(V). In 0.7M NaCl, pH 8.0, and artificial seawater (no organics), the Pu(V) formed was stable. In real seawater (with organic components), a rapid reduction of Pu(VI) to Pu(IV) was also observed. The Pu(V) formed in seawater was metastable; a very slow reduction to Pu(IV) occurred. This reduction was catalyzed by light. / Humic acid (obtained from marine sediments from the Bahama Islands), was added to 0.7M NaCl, pH 8.0 solutions to determine its effect on Pu redox reactions. The effect was similar to the reductions in seawater. Increasing the humic acid concentration decreased the amount of Pu(V) which was formed and favored the IV state. / The americium electromigration experiments showed a +0.12 net charge for the Am complexes formed in 0.7M NaCl solutions from pH 7.0 to 8.0. This value was smaller than the charge of +0.94 calculated from predicted speciation. / Source: Dissertation Abstracts International, Volume: 45-02, Section: B, page: 0547. / Thesis (Ph.D.)--The Florida State University, 1984.

Many chemical analyses are background-limited, that is, the lower limit of their applicable range is set by uncertainties in establishing the position of the background. Minimizing this uncertainty leads to useful improvements in analytical performance. This dissertation examines and compares digital data processing techniques which can be used for this purpose. Chapter 1 briefly reviews the fundamental aspects of data processing. In the subsequent Chapters, four projects involving background correction are then discussed. / The success of background correction by data processing depends mainly on the efficiency and reliability of the programs used. Attempts to improve these two important factors have mainly dealt with programming languages and with techniques of overall program design. The concept of reusable software will be introduced and its value, particularly in a research environment, will be discussed in Chapter II. / Chapter III deals with the qualitative aspects of background correction. Its goal is to improve spectral information. Only minimal spectral distortion is allowed. Five data processing techniques are described and their performance on simulated data sets, with better control of factors such as signal-to-noise ratio (S/N) and background conformation, is examined. The relationship between the design philosophy and correction efficiency is discussed. / Chapter IV deals with the quantitative aspects of background correction. Its goal is to improve the quality of quantitative information. Fourteen data processing techniques are described and evaluated. An attempt has been made to validate the procedures used in constructing the simulated sets. They are closely modeled on the Raman spectrum of dimethyl sulfone which is a suspected intermediate of sulfuric acid rain cycle. The optimal results show a compromise between noise amplification and background suppression. / Chapter V is an extended application of the optimal methods, developed in Chapter IV. They are applied to an infrared spectrum of a mixture of three classes of serum lipid which are of clinical interest. It is shown that these techniques are still effective in severe peak overlap cases, thus expanding their application range. / Source: Dissertation Abstracts International, Volume: 44-11, Section: B, page: 3394. / Thesis (Ph.D.)--The Florida State University, 1983.

The application of data enhancement techniques to digitized spectra allows more efficient utilization of the information, resulting in increased sensitivity and selectivity. Chapter I discusses the techniques used in this study, including ensemble averaging, digital filtering, correlation, least squares fitting, and background treatments. / In Chapter II, a study of simultaneous multicomponent analysis by computer enhanced infrared spectroscopy is presented. Cross-correlation and least squares fitting are used in three-component analyses under comparable conditions. Simulations are carried out to evaluate the effect of noise, degree of peak overlap, degree of peak width similarities, and various errors on the results. Each method is then applied in the analysis of the three major classes of serum lipids. Statistical comparison shows that least squares fitting gives slightly better results than cross-correlation. / Chapter III discusses the determination of ('13)CO(,2)/('12)CO(,2) ratios by infrared spectroscopy employing cross-correlation and least squares fitting. Small increases in the levels of ('13)CO(,2) over naturally occurring levels, as are encountered in clinical breath tests, are measured. The results from cross-correlation are better than those by least squares in this application. / Source: Dissertation Abstracts International, Volume: 44-11, Section: B, page: 3395. / Thesis (Ph.D.)--The Florida State University, 1983.