The electrospray survivability of B. subtilis spores and E. coli was tested in atmospheric mobility experiments. E. coli did not survive electrospray charging and desolvation, but B. subtilis did. Experimental conditions ensured that any surviving bacteria were charged, desolvated, and de-agglomerated. B. subtilis was also found to survive both positive and negative electrospray and subsequent introduction into vacuum conditions. Attempts were made to measure the charge distribution of viable B. subtilis spores using electrostatic deflection. From those experiments, it was found that either the spores do not become highly charged under the electrospray conditions used or only spores in a low positive or negative charge state survive.

An investigation of several solid sources for use in isotopic analysis by means of a mass spectrometer is reported. In particular, the compound copper acetylacetonate has been successfully employed to obtain ion currents corresponding to the copper isotopes. The second portion of this thesis deals with an energy filter method of reducing scattering effects in a mass spectrometer tube. / Thesis / Master of Arts (MA)

Isotopic abundances of the elements xenon, krypton, and cesium formed in the 14-Mev neutron fission of 238U have been measured using the mass-spectrometric method. The relative yields of some isotopes of krypton, strontium, zirconium, molybdenum, ruthenium, iodine, xenon, barium, cerium and neodymium were measured using a Ge(Li) detector. The ratios were normalized through isobaric nuclides, and absolute yields were obtained by normalizing the sum of the heavy-mass yields to 100%. A semi-empirical method has been developed for constructing neutron yield curves. Such a curve was used to obtain a primary-yield curve from the cumulative yields reported here. The results indicate that considerable structure might exist in the primary-yield curve at the higher excitation energy. / Thesis / Doctor of Philosophy (PhD)

<p> An inexpensive method was developed for the conversion of a high performance liquid chromatography (HPLC) system for use with 1 mm I.D. microbore columns. Chromatographic performance of the system was tested under both isocratic and gradient elution conditions, using a standard mixture of 16 polycyclic aromatic hydrocarbons (PAH).</p> <p> The microbore column HPLC was also coupled to a mass spectrometer equipped with a moving belt interface. Chromatographic performance under isocratic and gradient elution and mass spectral performance under scanning and selected ion monitoring modes were tested using the PAH standard.</p> <p> A marine sediment extract was subjected to qualitative and quantitative analysis for PAH. Qualitative results on the sample were obtained from a combination of retention indices, mass spectra, and retention times. Quantitation was performed by microbore column liquid chromatography-mass spectrometry (LC/MS) in the selected ion monitoring mode of operation. The method of calibration used was external calibration.</p> <p> The microbore column HPLC system exhibited good chromatographic behavior. Resolution, peak shape and short term retention time reproducibility were good, although, long term retention time fluctuations, due to changing mobile phase flow rates, were noted.</p> <p> The combination of microbore column HPLC with a moving belt interface and mass spectrometer gave excellent results. Problems commonly encountered with conventional column (4.6 mm I.D.) LC/MS, such as backstreaming, droplet formation, and splattering were greatly reduced, resulting in no apparent loss of chromatographic integrity and stable mass spectrometer operating conditions. These operating conditions proved to be most advantageous in the quantitative analysis of the marine sediment extract by selected ion monitoring.</p> / Thesis / Master of Science (MSc)

As mass analyzer technology has continued to improve over the last fifty years, the prospect of field-portable mass spectrometers has garnered interest from many research groups and organizations. Designing a field portable instrument entails more than the scaling down of current commercial systems. Additional considerations such as power consumption, vacuum requirements and ruggedization also play key roles. In this research, two avenues were pursued in the initial development of a portable system. First, micrometer-scale mass analyzers and other electrostatic components were fabricated using silicon on insulator-deep reactive ion etching, and tested. Second, the dimensions of an ion trap were scaled to the millimeter level and fabricated from common metals and commercially available vacuum plastics. This instrument was tested for use in ion isolation and collision induced dissociation for secondary mass spectrometry and confirmatory analyses of unknowns. In addition to portable instrumentation, miniature mass spectrometers show potential for usage in process and reaction monitoring. To this end, a commercial residual gas analyzer was used to monitor plasma deposition and cleaning inside of a chamber designed for laser ablation and soft landing-ion mobility to generate metal-main group clusters. This chamber was also equipped for multiple types of spectral analysis in order to identify and characterize the clusters. Finally, a portion of this research was dedicated to method development in sample collection and analysis for forensic study. A new method for the analysis of illicit chemistries collected via electrostatic lifting is presented. This method incorporates surface-enhanced Raman microscopy as a prescreening tool for nanoextraction and nanospray ionization mass spectrometry.

Analysis of urinary hormone levels can be used to identify sex and breeding patterns in amphibians. This is especially important for ensuring the survival of endangered species. The most common way to determine hormone levels is enzyme-linked immunosorbent assay (ELISA); however, there is the possibility of cross-reactivity with this technique, and only one hormone can be monitored per plate, limiting efficiency. In this study, the effectiveness of liquid chromatography coupled to mass spectrometry (LC-MS/MS) was evaluated in terms of sensitivity, repeatability, and through-put in monitoring hormone levels in Anaxyrus boreas boreas (boreal toads). Urine samples were collected from ten different female Boreal toads over a three-year period and monitored for estrone, â-estradiol, estriol, 17á-ethinylestradiol, corticosterone, testosterone, and progesterone. To account for differences in urine concentration, creatinine (a metabolic breakdown product) was used to normalize all samples as it is typically present at a constant concentration. Prior to chromatographic analysis, all samples underwent a solid phase extraction (SPE) clean-up. Hormones in the estrogen class were derivatized via dansylation prior to analysis to enhance detection sensitivity. An Agilent 1290 Liquid Chromatograph coupled to an Agilent 6460 Triple Quadrupole Mass Spectrometer was used to quantitate hormone levels. The extraction method developed proved to be reliable and reproducible with percent recoveries in quality control samples ranging from 80%-120%. Using LC-MS/MS and derivatization, limits of quantitation as low as 0.001 parts-per-billion (ppb) were achieved for estrogens and 0.100 ppb for androgens. Ultimately, the method optimized for hormone analysis using LC-MS/MS showed to be as reliable as ELISA while also being less expensive per sample and more robust.

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