Stir bar sorptive extraction for the analysis of beverages and foodstuffs
Thesis (PhD (Chemistry and Polymer Science))--University of Stellenbosch, 2008.
The main goal of this study was the development of new technologies based on modern analytical techniques for analysis of volatiles in wines. Due to the exponential growth of the wine industry and consumer demands for an enjoyable, safe-to-consume, and high quality product, the need for arose for methodologies aiding the understanding of wine better arose. Chemical analysis is a valuable way of studying the composition of wine in depth. Very sophisticated instrumentation is available nowadays but almost always the sample needs to be cleaned up or concentrated before such analysis. This study investigates the use of stir bar sorptive extraction (SBSE) as such a technique. It is shown that SBSE combined with gas chromatography-mass spectrometry (GC-MS) is extremely suited for a wide number of analyses and during the course of the study the technique was applied for troublesome analytical challenges in various beverages and foodstuffs. The study focuses on the development of a screening technique for volatiles in wine using SBSE and the application of the data to various chemometrical techniques for classification purposes. A second part of the study shows the applicability of SBSE for extraction of pesticides, contaminants and preservatives from wine, water, lemon flavoured beverages and yoghurt. The method is also elaborated upon by development of faster analysis methods for wine and beer and the investigation of using SBSE for headspace sampling of wine. In all the applications, SBSE technology was shown to be sensitive, repeatable, robust and very simple to use.