Improved ruggedness and resolution for kinetic-based analyses
Abstract
The major goal of this thesis is to evaluate alternative data-processing approaches to improve the ruggedness and resolution for kinetic-based determinations. The thesis is presented in three parts. Part I of the thesis describes a study designed to improve the ruggedness of quantitative determinations based on unsegmented flow system. The reaction of hydrogen peroxide with iodide catalyzed by molybdate was chosen as a model system with conditions adjusted to follow pseudo-first-order kinetics. Effects of changes of pH as well as concentrations of iodide and molybdate were evaluated using four different data-processing options. All data-processing options yield linear calibration plots and had similar degrees of imprecision. The new options are 10- to 70-fold less dependent on changes for variables studied. Part II of the thesis describes a study designed to extend a data-processing approach developed for chemical reactions to physico-chemical processes. Atomic absorption spectroscopy with electrothermal atomization was chosen as a model system. Five metal ion solutions were tested. Effects of atomization temperature were evaluated using three options. All data-processing options yield linear calibration plots and the deconvolution option is 7- to 72-fold, and 1- to 18-fold less dependent on temperature than the conventional peak-height and peak-area options, respectively. Part III describes a study to evaluate a new approach to the resolution of overlapped chromatographic peaks. Experimental data of acetic and formic acids were used to synthesize overlapped peak area vs. time data and asymmetrical sigmoid functions were fit to these data to resolve their individual components. Results show that our models perform at least as well as the more conventional perpendicular drop method for base-line to partially resolved peaks (R $>$ 0.76), and give better resolution for badly overlapped peaks (R $<$ 0.45).
Degree
Ph.D.
Advisors
Pardue, Purdue University.
Subject Area
Analytical chemistry
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