Document Type
Thesis - University Access Only
Award Date
2009
Degree Name
Doctor of Philosophy (PhD)
Department / School
Chemistry
Abstract
Analytical methods are routinely defined by parameters such as selectivity, accuracy, precision, and detection limits. However, since we now have knowledge of the extent of hazards that exist, I propose that analytical methods should also be defined by their environmental impact. Previously, these definitions did not exist. In the first part of this dissertation a Green Assessment was developed to create those definitions. In the assessment, a system of quantitatively evaluating the environmental and health impacts was constructed where five criteria, health hazard, safety hazard, environmental hazard, waste generation, and energy use of a method were evaluated based on the degree of severity of risk and depicted in a symbolic fashion. The application of the Green Assessment to five environmental methods for quantifying polycyclic aromatic hydrocarbons in water samples clearly exhibited the ability of the assessment to differentiate between methods. Having a systematic process by which chemicals of interest are separated from a matrix then identified and/or measured is the basis for chemical analysis. In the second part of this dissertation a new regulatory method for the extraction and quantification of neomycin B and neomycin C from animal feeds was developed as a potential alternative to the AOAC standard microbiological method which lacks accuracy, precision, and selectivity. Separation of neomycin Band neomycin C was achieved with cation-exchange chromatography. Fluorescence detection of neomycin was achieved following post-column o-phthalaldehyde derivatization. The method sample range covers additive levels of neomycin (50- 0.005 %wt./wt.) found in types A, B, and C medicated feed products. The linear range allows for quantification of 50 - 150% of expected sample concentrations. Average recovery from spiked samples over the range of medicated levels was 99.0% with %RSD of 3.66. Recent advances in extraction technology, including Accelerated Solvent Extraction (ASE) and Microwave-Assisted Extraction (MAE), are being utilized to replace the more time-consuming and solvent-intensive Soxhlet extraction. The final part of this dissertation investigated the fit of the dynamic extraction process in Soxhlet, Soxtec, ASE, MAE, and ultrasound to the hot-ball model and compared the kinetics of these techniques. The results of the study showed that the experimental extraction data for each of the techniques did fit the hot-ball model and the experimental diffusion coefficients for each of the enhanced extraction techniques were at least one order of magnitude greater than the diffusion coefficient of the Soxhlet extraction.
Library of Congress Subject Headings
Analytical chemistry
Green chemistry
Format
application/pdf
Number of Pages
172
Publisher
South Dakota State University
Recommended Citation
Driver, Julee L., "Investigations Into Chemical Analysis : Assessing Greenness, Quantifying Isomers, and Modeling Diffusion" (2009). Electronic Theses and Dissertations. 1575.
https://openprairie.sdstate.edu/etd2/1575
