MICROEXTRACTION TECHNIQUES IN THE CHROMATOGRAPHIC ANALYSIS OF ENVIRONMENTAL WATER CONTAMINANTS

Abstract

This thesis presents the developments of two microextraction techniques, namely, dispersive liquid-liquid microextraction (DLLME) and alternative-fibre solid-phase microextraction (SPME), coupled with gas chromatography-mass spectrometry for the analysis of sixteen polycyclic aromatic hydrocarbons (PAHs) and fifteen semi-volatiles in water samples. In the DLLME projects, minimal volumes of environmentally friendlier low-density organic solvents were used as extractants, and the centrifugation step, normally needed in conventional DLLME, was bypassed through the use of a demulsification solvent to separate the phases that occur after DLLME. Together with the use of the specially designed vials, the entire procedure could be fully automated and completed, in ca. ten minutes. In the alternative-fibre SPME part of the work, the extraction capabilities of three different forms of a zinc-coated iron wire: Conditioned bare wire, conditioned bare wire with solvent coating (a combination of SPME and liquid-phase microextraction) and an etched wire with solvent coating, were investigated for the enrichment of PAHs from water. An environmentally friendlier etching method was also proposed as an alternative to the use of the highly toxic hydrofluoric acid.