Development of sensitive methods for chemical analysis requires comprehensive understanding of the various experimental contributions to signal, interferences, and noise. This premise was applied to the development of multiphoton photoionization spectroscopy and optical polarimetry. For the former, two methods were attempted to improve performance in polar solutions. Auto-by-cross correlation was implemented as a signal processing scheme for quantifying transient signals, which included photoionization. Careful analysis of background fluctuations and signal-to-noise ratio behavior showed that, while the method itself was useful, certain peculiarities of its implementation with photoionization prevented full realization of the experimental goals. The second innovation for photoionization was to replace most of the polar solvent with nonpolar solvent, and sequester the polar solvent and analyte in the interior of a reverse micelle. Analysis of the background noise showed that noise reduction was excellent; solvent noise was reduced nearly to the level of heptane. The photoionization signal also decreased, such that no gain in signal-to-noise ratio was realized. However, it was shown that the microemulsion solutions offered a much better environment for analysis of aqueous-soluble compounds. It was also shown that microemulsions provided a means of performing analyses by photoionization that were otherwise impossible, such as at nonneutral pH. Numerical simulations were employed extensively in the development and evaluation of a laser-based optical polarimeter. Numerous simulations showed the optimum operating conditions for a Faraday rotator-based polarimeter, and provided an accurate means of evaluating previously published predictions. An experimental polarimeter was also constructed, and the source noise was manipulated to correspond with that of the simulations. It was shown that, when all experimental variables were taken into account, the simulations yielded very accurate predictions of polarimeter behavior.

Flow analysis procedures have used a wide variety of detectors. Magnetic susceptibility and graphite furnace atomic absorption spectrometry are two detection techniques with limited applicability to flow procedures. Most magnetic susceptibility balances are not applicable to flowing streams. The use of GFAAS has been limited due to the presence of several timing problems. The Johnson Matthey magnetic susceptibility balance is readily adaptable to flowing streams. Analytical parameters such as detection limits and sensitivity were determined for several ferromagnetic and paramagnetic species. Retention of the metal cations on a column of ion exchange resin situated within the poles of the magnets allowed preconcentration of the cations. The passage of a stream of borohydride through the column containing the immobilized cations caused a dramatic increase in signal. A simple method for calibrating the temperatures of the drying stage of the GFAAS program based on the visual observation of the melting of a number of compounds is presented. Recirculating loop technology was used to devise an interface between a flow injection manifold and a GFAAS system. The use of a recirculating loop eliminates the timing problems common to FIA-GFAAS. A number of Pb solutions of known concentration were analyzed and accurate results obtained. Preconcentration of Pb on C-18 columns and various ion exchange resins was performed before introduction into the recirculating loop. Once the system had been shown to yield accurate results, wine samples were analyzed. The determination of Pb in wines is difficult due to the low concentration of Pb in wines and the complex matrix. Flow analysis procedures were used to isolate the Pb from the matrix before analysis by GFAAS.

The goal of this research has been to enhance sample decomposition techniques through the coupling of flow technology with current sample digestion methodology in order to approach the characteristics of an ideal digestion system--one which is rapid, minimizes sample and reagent consumption, avoids analyte loss or contamination, rapidly transfers the resulting digest into the detector for measurement, and is amenable to automation. A stopped-flow, high pressure manifold incorporating a resistively heated thermal oven was developed for the on-line dissolution of slurried samples having a predominantly organic matrix. The manifold, which was directly coupled with a flame atomic absorption spectrometer, was determined to be most applicable to samples in which the analytes were loosely bound to the bulk material. This was a consequence of the limited oxidation potential of the system resulting from insufficient headspace volume for the expansion of nitrous oxides which are believed to be crucial intermediates in the digestion process, and rapid overpressurization of the manifold due to a lack of control over the rate of energy input to the system. A stopped-flow, high pressure manifold incorporating a microwave oven was subsequently developed to overcome the limitations of the thermal oven manifold. A microwave heated glass reaction column provided ample headspace for the expansion of gaseous reaction products and the use of power programming allowed for control of the energy flux introduced to the system. A dual stage manifold depressurization system was designed and interfaced via an autosampler to both a flame atomic absorption and an inductively coupled plasma atomic emission spectrometer for the determination of trace elements in solid samples. A study of the manifold operating parameters, such as flow rate, carrier stream composition, residence time, energy input, and gas-liquid separation was conducted in this work. Slurry sample preparation and handling and instrumental response to samples in concentrated acid matrices were also investigated.

Atmospheric chemistry has primarily focused on outdoor environments for many decades. Plenty of models based on the findings of outdoor atmospheric researchers have been built to deepen the understanding of outdoor environments and predict how certain changes in specific parameters may affect the overall atmosphere. The same cannot be said for indoor environments, which remain relatively unknown despite the fact that humans in developed countries spend the vast majority of their lives in indoor environments. This thesis seeks to provide an early look at the makeup of indoor surface films, specifically at their molecular compositions and thicknesses. These characteristics are important for understanding how surface films, a major route of human exposure to compounds which can negatively affect health, begin to form and how they evolve over time with exposure to other indoor species. Two types of surface films were analyzed in this thesis: lab-created surface films of commercial household cleaners sprayed onto glass plates, and “real-world” surface films extracted from areas of a high-traffic lecture hall on a college campus. Samples were extracted with an Indoor Surface Extractor (ISE) and analyzed with quadrupole ion trap mass spectrometry (MS), Orbitrap MS, and/or Fourier-transform ion cyclotron resonance MS. Resulting mass spectra were used to identify individual components observed in the surface films. Both listed ingredients in the household cleaners and compounds not listed as ingredients were observed in their surface film extracts’ mass spectra; quaternary amine compounds (QACs) were observed in many of the real-world surface film extract mass spectra, likely present from increasing COVID-19 sanitary measures. In a second part of this thesis, quantification of organic material in surface films was executed with aerosol MS. Citric acid was used as a proxy for the organic surface film matrix in order to build calibration curves for the response of organic material relative to two different internal standards. These calibrations were then applied to some of the same surface film extracts analyzed by qualitative MS methods to estimate the thicknesses of the films that were extracted; the results fell in line with previously published estimates of indoor surface film thickness, indicating that the experimental parameters being used are in the correct general range and can be fine-tuned for future quantification studies.

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