Development of reversed-phase two-dimensional liquid chromatographic systems for the separation of complex samples

  • Michael J. Gray

Western Sydney University thesis: Doctoral thesis

Abstract

This thesis describes a developmental process required for the construction and optimisation of two-dimensional liquid chromatographic systems. The text encompasses much of the difficulties and provides a frame work for achieving positive results. The hardware requirements and the concepts for successful completion of heart-cutting and comprehensive modes of separation are addressed. Low molecular weight polystyrenes play an essential role in providing a model framework or theme for the development of two-dimensional liquid chromatographic systems. Low-molecular weight oligostyrenes were initially used to provide a theoretical assessment of combinations of liquid chromatographic systems. Interpretation of theoretical results then allowed for the development of a heart-cutting two-dimensional liquid chromatographic system for the separation of oligostyrene complex samples. This allowed for practice to be compared with the theoretical results, which are presented and provided direction as to what attributes of a two-dimensional liquid chromatographic system are beneficial. Petroleum oils are one of the most complex mixtures found in the natural environment and are included to provide a real-world application that demonstrates the potential power of comprehensive two-dimensional liquid chromatographic systems. Orthogonality is a central theme throughout the whole thesis. Separation correlation is shown to be advantageous in certain instances in the evaluation of hybrid stationary phases, as shown in the analysis of a low molecular weight polystyrene sample. The thesis finishes by the incorporation of monolithic separation media as an alternative second dimension stationary phase support. A method is discussed that allows for a substantial increase in the volume and concentration loading of two-dimensional liquid chromatographic systems that employ monolithic chromatography columns in the second dimension. This is important since volume overloading and concentration overloading in the second dimension can reduce separation performance and hence the final chapter provides a new direction for research.
Date of Award2005
Original languageEnglish

Keywords

  • liquid chromatography
  • chromatographic analysis
  • oligostyrenes

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