Abstract


Fox, James D., The analysis of selenocyanate from the broth cultures of selenium-resistant bacteria using solid-phase extraction and capillary electrophoresis. Master of Science (Chemistry), August, 2008, Sam Houston State University, Huntsville, Texas, 67pp. (pdf version of this thesis)

Purpose

The purpose of this research was, in part, to develop a method for the pre-concentration and extraction of selenocyanate from the liquid cultures of selenium-resistant bacteria using solid-phase extraction and capillary electrophoresis with photodiode array detection. An environmental soil bacterium (130404) growing on a complex medium displayed an inherent resistance to various forms of selenium and had the ability to convert them into elemental and insoluble selenium and into organoselenides. Experiments using ion chromatography-inductively coupled plasma-mass spectrometry indicated that this bacterium was also able to convert small quantities of selenate into selenocyanate. The goal was to develop a method to pre-concentrate selenium species in broth cultures of metalloid resistant bacteria (via solid-phase extraction) and determine the concentration of these chemical species using capillary electrophoresis. Experiments were also carried out to examine the effect of various selenium-containing species on the growth of 130404 and an E. coli clone (1VH) by examining the optical density of the culture over time. Similar experiments were carried out with a Bacillus spp. to determine such factors as nitrate dependence and ampicillin resistance. The headspace of liquid cultures of 1VH and the Bacillus was also examined using solid-phase microextraction and gas chromatography with fluorine-induced sulfur chemiluminescence detection. Both organosulfides and organoselenides were observed in the headspace of selenium-amended cultures, indicating their ability to bioprocess the selenium-containing species.

Experiments also examined the effect of various selenium-containing species on the growth of 130404 and E. coli clone (1VH) by examining the optical density of the culture over time. Similar experiments were done with a Bacillus spp. to determine such factors as nitrate dependence and ampicillin resistance. The headspace of liquid cultures of 1VH and the Bacillus was also examined using solid-phase microextraction and gas chromatography with fluorine-induced sulfur chemiluminescence detection. Both organosulfides and organoselenides were observed in the headspace of selenium-amended cultures, indicating their ability to bioprocess the selenium-containing species.

Keywords: selenocyanate, capillary zone electrophoresis, bacteria, growth medium, solid phase extraction

 

Thomas G. Chasteen
Thesis Director

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