Physical Sciences and Mathematics Commons^™

Development Of Chemometric Models And Calibration Transfer For Rapid Diesel And Jet Fuel Analysis Using Near Infrared Spectroscopy, Christopher Matthew Larkin

Chemistry & Biochemistry Theses & Dissertations

Fuel quality assurance and analysis, as it pertains to the United States armed forces, is crucial for maintaining operability and upholding safety regulations with respect to fuel class. Currently a great amount of effort, money and manpower are dedicated to this task as fuel analysis takes place in off-site laboratories where quality assessment and property determination is performed manually by highly qualified lab technicians. This presents the military with a logistics problem with respect to refueling, transport, and fuel storage as the typical tum-around time is 1-2 weeks. In this thesis it has been demonstrated that near-infrared spectroscopy, in conjunction …

Solvent Dependent Morphologies In Thiol-Ene Photopolymerization: A Facile Route To Synthesis Of Resorcinarene Nanocapsules, Zaharoula Marie Kalaitzis

Chemistry & Biochemistry Theses & Dissertations

Synthesis of morphologically distinct polymeric nanostructures is vital for their wide ranging applications from nanomedicine to material science. Among various polymeric nanostructures, nanocapsules in particular have attracted a lot of attention as nanoreactors and drug delivery vehicles in nanomedicine. Often, synthesis of nanocapsules is achieved by template-based approaches. A direct, template-free method for the fabrication of nanocapsules and a variety of other morphologically distinct polymeric architectures was developed. The photopolymerization of a resorcinarene thiol-ene surfactant in various solvents lead to the formation of nanocapsules, nanoparticles, fibers, distorted honeycomb-like lattices, and sheets. The progress of the polymerization reaction and the morphology …

Theoretical Studies Of 2,3 -Sigmatropic Rearrangements Of Allylic Selenoxides And Selenimides, Craig A. Bayse, Sonia Antony

Chemistry & Biochemistry Faculty Publications

Density-functional theory is used to model the endo and exo transition states for [2,3]-sigmatropic rearrangement of allylic aryl-selenoxides and -selenimides. The endo transition state is generally preferred for selenoxides if there is no substitution at the 2 position of the allyl group. Based upon the relative energies of the endo and exo transition states, enantioselectivity of rearrangements is expected to be greatest for molecules with substitutions at the 1- or (E)-3- position of the allyl group. Ortho substitution of a nitro group on the ancillary selenoxide phenyl ring reduces the activation barriers, increases the difference between the endo and exo …

Section Abstracts: Chemistry

Virginia Journal of Science

Abstracts of the Chemistry Section for the 87th Annual Meeting of the Virginia Academy of Science, May 27-29, 2009, Virginia Commonwealth University, Richmond Virginia.

The Use Of Fourier Transform (Ft) Surface-Enhanced Raman Scattering For Biochemical Analysis, Robert Butler Jeffers

Chemistry & Biochemistry Theses & Dissertations

Surface-enhanced Raman scattering (SERS) is a powerful spectroscopic technique that has created exciting opportunities in the field of bioanalytical chemistry, where it combines ultrasensitive detection of biologically relevant molecules with vibrational spectroscopy. Due to the difficulties in preparing reproducible SERS active substrates, SERS has been mainly used as a qualitative tool. In order for SERS to be utilized as a viable tool for quantitative analysis, simple, facile SERS substrates which generate clean, highly reproducible signals must be developed. This dissertation deals with the evaluation of three different methods of SERS that led to the development of a novel substrate for …

Anthropogenic Osmium In Rain And Snow Reveals Global-Scale Atmospheric Contamination, Cynthia Chen, Peter N. Sedwick, Mukul Sharma

OES Faculty Publications

Osmium is one of the rarer elements in seawater, with typical concentration of ≈10 x 10^-15 g g^-1 ( 5.3 x 10^-14 mol kg^-1. The osmium isotope composition (¹⁸⁷Os/¹⁸⁸Os ratio) of deep oceans is 1.05, reflecting a balance between inputs from continental crust (≈ 1.3) and mantle/cosmic dust (≈ 0.13). Here, we show that the ¹⁸⁷Os/¹⁸⁸Os ratios measured in rain and snow collected around the world range from 0.16 to 0.48, much lower than expected (>1), but similar to the isotope composition of ores (approximate to 0.2) …

Electrospray And Photoionization Mass Spectrometry For The Characterization Of Organic Matter In Natural Waters: A Qualitative Assessment, William C. Hockaday, Jeremiah M. Pucell, Alan G. Marshall, Jeffery A. Baldock, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

Fourier-transform ion cyclotron resonance mass spectrometry (MS) has demonstrated potential to revolutionize the fields of limnology and chemical oceanography by identifying the individual molecular components of organic matter in natural waters. The use of MS for this purpose is made possible by the electrospray technique which successfully ionizes polar, nonvolatile organic molecules. Another recently developed ion source, atmospheric pressure photoionization (APPI), extends MS capabilities to less polar molecules. This article presents early results on the application of APPI MS to natural organic matter. We compare APPI MS and electrospray MS data for dissolved organic matter from Lake Drummond (Virginia, USA). …

Export Of Terrestrial Dissolved Organic Matter Along A River To Ocean Transect Of The Lower Chesapeake Bay Investigated By Advanced Analytical Techniques, Rachel Leigh Sleighter

Chemistry & Biochemistry Theses & Dissertations

Ultrahigh resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) has proved essential for the complete separation of the thousands of peaks present in natural organic matter (NOM), a complex assemblage of organic molecules present in water, soils, and sediments. An improved understanding of its composition is crucial to understand how pollutants interact with NOM and how NOM cycles through global carbon cycles.

Optimizing the acquisition and handling of the FTICR mass spectra is the first step to obtaining high quality data. A simple method to internally calibrate the peaks in the complex spectra, using naturally present fatty …