Chapter 12
Supercritical Fluid Extraction New Directions and Understandings 1
Mary Ellen P. McNally, Connie M . Deardorff, and Tarek M . Fahmy
Downloaded by UNIV OF ARIZONA on January 18, 2013 | http://pubs.acs.org Publication Date: May 8, 1992 | doi: 10.1021/bk-1992-0488.ch012
Agricultural Products, Experimental Station, E402/3328B, E. I. du Pont de Nemours and Company, Wilmington, D E 19880-0402
Supercritical fluid extraction (SFE) has been demonstrated as a technique that has eliminated some of the tedious steps of current liquid-liquid and solid-liquid extraction procedures. SFE also offers cleaner extracts, less sample handling and equivalent or better recoveries to conventional technologies. As a technique, it is cost effective, time efficient and low in solvent waste generation. The areas which need to be addressed to bring SFE into the routine laboratory are precision/reproducibility and multi-sample analysis. Without development in these directions, competition with conventional methodology does not exist. As demonstrated by applications to Agricultural Products, experiments will be presented which show the feasibility of using SFE as a routine analytical tool in sample preparation. The adaptation of supercritical fluid extraction (SFE) in routine residue and metabolism analysis as well as other extraction/separation laboratories and applications has been slow. This is despite the demonstrated feasibility of using SFE for the removal of sulfonylureas, phenylmethylureas and their metabolites from soil and plant materials (1-2), as well as widespread demonstrated use of supercritical fluid extraction for other applications (3-6). The reason for this is simple. Although automated, SFE extraction apparatus typically only analyzes a single sample at a time. The technique could not compete effectively with the productivity of an experienced technician performing many sample extractions simultaneously. In essence, with a one vessel automated supercritical fluid extractor, operator attendance is high and throughput is about the same or even less than current conventional liquid-liquid and solid-liquid extraction techniques. 1
Current address: Dupont Chemicals, Fluorochemicals Research and Development, Chamber Works, K37, E . I. du Pont de Nemours and Company, Deepwater, NJ 08023 (X)97-6156/92/0488-0144$06.25A)
