Development and validation of novel solventless microextraction techniques in gas chromatography

Among the prior demands in current sample preparation for organic trace analysis are sensitivity, ease of automation and solvent exclusion. One approach to meet these demands has been the development of microextraction techniques, where the amount of extraction phase is very small compared to the sample phase. Today, microextraction techniques are used in current analytical methods from all fields. This thesis provides an overview on the recent developments in solventless microextraction techniques, with special emphasis on techniques providing full automation, starting from the first open-tubular trap techniques in the mid-1980s to recent devices utilizing sorbent packed needles. Different implementations of in-needle microextraction are discussed with their characteristic benefits, shortcomings and possible sampling modes. In this context, solid phase dynamic extraction (SPDE) was investigated for its applicability in quality control analysis of 196 German red wines. To that purpose, a fingerprinting database was created using commercial available chromatogram comparison software. 22 flavor relevant alcohols and esters have been quantified, also, to monitor the long term extraction performance of the SPDE needles, which showed constant results for up to 400 extractions using one extraction needle tip. A novel in-tube extraction (ITEX) device for headspace sampling has been evaluated for environmental and food analysis. To that end, five commercially available and six custom prepared sorbent traps have been evaluated for their extraction efficiency for over 50 analytes from different classes. They cover aromatics, heterocyclic aromatics, halogenated hydrocarbons, fuel oxygenates, alcohols, esters and aldehydes. During this course, the benefits of the use of adsorbent or absorbent materials, depending on the application, were shown, as well as the potential of mixed bed traps. Method detection limits in the low ng L-1-range were achieved for compounds of importance for drinking water quality, which is much lower ...