Electrically Controlled Formation and Release of Admicelles for Solid Phase Extraction
Solid phase extraction is one of the most widely used methods to concentrate diluted compounds in a solution. Substances can be extracted into admicelles and hemimicelles, which are surface adsorbed micelles and surfactant monolayers, respectively. Investigations of the electrical control of surfact...
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| Format: | Others |
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TopSCHOLAR®
2014
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| Online Access: | http://digitalcommons.wku.edu/theses/1334 http://digitalcommons.wku.edu/cgi/viewcontent.cgi?article=2337&context=theses |
| Summary: | Solid phase extraction is one of the most widely used methods to concentrate diluted compounds in a solution. Substances can be extracted into admicelles and hemimicelles, which are surface adsorbed micelles and surfactant monolayers, respectively. Investigations of the electrical control of surfactants on surfaces for the purpose of analyte preconcentration prior to chromatographic analysis are presented. The surfactant layer serves as the “stationary phase” in a solid phase extraction sorbent scenario. Analytes are adsorbed on this layer, and then released from the solid phase via surfactant removal. The attachment and removal of the surfactant are controlled by means of an electric field. Because the surfactant-analyte association is released by electrical control, organic solvents, which are used in conventional solid phase extraction, are not required. Therefore, this procedure is advantageous for method development and environmental concerns. Presented is the preconcentration of a test probe, 2-naphthol, using electrical control of the formation and release of dodecyl sulfate on planar gold, gold coated stainless steel, and a porous stainless steel frit, using impedance spectroscopy to observe the layer formation with various surfactant concentrations and applied potentials. |
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