Development of a miniature, continuous measurement, stochastic perturbation gas chromatograph

Abstract

Gas chromatography is one of the most widely used analytical chemistry techniques for separating and analyzing chemical compounds. Chromatographic methods are used to identify constituent species within a compound and determine the purity and relative concentrations of those species. Current gas chromatographs are heavy, bench top instruments that require large capital expenditures, kilowatt power sources, and trained technicians. Additionally, traditional chromatographic measurements are non-continuous. The first part of this thesis explores the application of stochastic system identification techniques applied to chromatography to enable continuous chromatographic measurements, multiplexing of instrument components, and the ability to optimally tune instrumentation parameters and reduce chromatogram noise. The second part of this thesis explores the development of a miniaturized, standalone gas chromatograph. A handheld, low-cost gas chromatograph has been developed over the course of five device generations, through the implementation of localized heating techniques, on-demand gas generation, and the integration of electrical, mechanical, and chemical processes into a compact volume. Characterization of the device shows comparable operating parameters and performance to equivalent bench top instruments at 0.5% total cost and 0.03% total volume. These contributions reduce the barrier-to-entry for performing high quality chemical measurements, and enable more widespread use of chromatography in monitored, closed-loop, remote operation and automated systems.