New directions in non-porous membrane extraction

Complex biological and environmental samples require a high degree of selectivity in order to determine components therein. Sensitivity measures, such as analyte pre-concentration are often required for assessing composition quantitatively. Use of membranes and especially non-porous membranes for extraction purposes offers in many cases the desired measure of selectivity and sensitivity for trace analysis from such samples. Selected species can be either permanently charged, ionogenic or neutral, and range in size from protons to proteins. The result of the extractions is often excellent cleanup of the matrix and a decrease in detection limits. Another salient feature with these systems is that they offer an extremely low consumption of potentially hazardous, organic solvents. The work in this thesis has focused on novel approaches within the field of non-porous membrane extraction, including system integration and automation, miniaturisation and extensions of technical scope and applicability. Integration has been designed to suit a number of important techniques, such as normal-phase and reversed-phase liquid chromatography (LC), capillary-LC, gas chromatography (GC), capillary electrophoresis (CE) and continuous-flow systems (FIA/SIA). The development of a miniaturised membrane unit, carrying a single hollow fibre, was devised and integrated with capillary-LC and with CE. An easy connection between membrane based liquid-liquid extraction and GC has been proposed. Extending the applicability of non-porous membrane extractions, antibodies have been used for selective recognition and trapping.