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Latex-coated stationary phases for preconcentration and separation in capillary electrochromatography

Hutchinson, JP 2004 , 'Latex-coated stationary phases for preconcentration and separation in capillary electrochromatography', PhD thesis, University of Tasmania.

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This work presents a systematic study on the use of latex-coated stationary phases for
on-column ion-exchange preconcentration of anions by capillary
electrochromatography with elution by a transient isotachophoretic gradient.
Fully functionalised quaternary ammonium latex particles were
electrostatically bound to open tubular (OT) capillaries and porous monolithic
capillary columns. These columns were characterised and provided a reproducible
and simple means for creating ion-exchange stationary phases with reversed
electroosmotic flow. Monolithic columns provide a chromatographic support of high
surface area, high phase ratio and are highly permeable. Adsorption of latex-particles
provides superior mass-transfer properties ideal for ion-exchange preconcentration
and ion-exchange capillary electrochromatography (IE-CEC). The prepared columns were characterised by their retention in IE-CEC when
the ion-exchange interaction was varied through manipulating the strength and nature
of the competing ion. Porosimetry and scanning electron microscopy were used to
characterise the monolithic surface and architecture. Up to 300,000 plates/column
were achieved using latex-coated silica monolithic columns and 164,000
plates/column were achieved on methacrylate analogues. Both silica and
methacrylate latex-coated monolithic columns were of similar capacity and around 20
times greater when compared to OT counterparts. A monolayer coverage of latex
particles was not evident on the monolithic columns created and resulted in mixed
mode interaction for the separation of organic anions on a polymer support.
Multi-mode columns were created using zero-dead volume unions to attach a
second capillary segment for the purpose of separation and detection and allowed
individual optimisation of the discrete segments. Decoupling of the preconcentration column allowed in situ preconcentration of a river water sample, which was brought
back to the laboratory for analysis.
Novel discontinuous electrolyte combinations were used to increase the range
of analytes which could be preconcentrated and detected. Alkylsulfonates were found
to be ideal strong electrolytes of low electrophoretic mobility and were able to
efficiently elute a large range of inorganic and organic anions. Further efforts to
increase the range of anions which can be preconcentrated and detected included the
use of a miniaturised capacitively coupled contactless conductivity detector and
indirect UV detection.
High capacity monolithic columns were suitable for sample-cleanup
procedures and were applied to the preconcentration of iodide in Southern Ocean
seawater. Detection limits of 11 pM were achieved for iodide when selective
focusing occurred at the isotachophoretic boundary using IE-CEC.

Item Type: Thesis - PhD
Authors/Creators:Hutchinson, JP
Keywords: Capillary liquid chromatography, Ion exchange chromatography, Stationary phase (Chromatography), Chromatographic analysis
Copyright Holders: The Author
Copyright Information:

Copyright 2004 the Author - The University is continuing to endeavour to trace the copyright
owner(s) and in the meantime this item has been reproduced here in good faith. We
would be pleased to hear from the copyright owner(s).

Additional Information:

Thesis (Ph.D.)--University of Tasmania, 2004. Includes bibliographical references

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