André J. de Villiers
Title: Associate Professor
Office: 1044 De Beers Building
Phone: +27 (0)21 808-3351
Fax: +27 (0)21 808-3360
PhD, University of Stellenbosch (SA), 2004
Post-doc studies, Pfizer Analytical Research Center, Gent University (Belgium), 2004-2006
Liquid chromatography, Gas chromatography, Wine chemistry, Mass
The focus of the research is on new developments in the field of separation sciences. These include the areas of ultra-high pressure and high temperature liquid chromatography, comprehensive chromatographic techniques, gas chromatography-olfactometry and innovative sample preparation techniques. Within the context of Stellenbosch these techniques are applied primarily to as powerful tools in the bourgeoning new field of wine science.
Comprehensive chromatographic techniques are based on the coupling of two separation methods. Because orthogonal information is obtained in this manner, tremendously improved resolving power is the result. While GCxGC methods are nowadays established as powerful separation tools, complications involved in coupling liquid-based separation systems has so far limited their application. Research in our laboratory focuses on designing powerful LCxLC systems to be used together with MS detection to unravel the exceedingly complex samples such as the phenolic fractions of wine.
Ultra-high-pressure and temperature liquid chromatography:
Exciting new developments in the field of LC during recent years has lead to significant improvements in the separations achievable. These include the use of elevated pressures (up to 1000 bar) and temperatures (up to 200?C). However, each of these approaches presents practical and fundamental difficulties. Research in this field is based in the first instance on fundamental possibilities and limitations using established chromatographic theory. At the same time the promise of these methods for several real-life applications is being demonstrated.
This is a new field in our group, where the aim is the use a ‘sniff-port’ and human panels as detectors (GC-olfactometry or GC-O). The human sense of smell is in most cases more sensitive than instrumental detectors, and provides additional information on the odour-active content of volatile fractions. Thus the application of GC-MS-O for flavour characterization of numerous samples, notably wine-related, opens an exciting new field of research.