Author
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KING, JERRY |
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Submitted to: Journal of Association of Official Analytical Chemists International
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/1/1998 Publication Date: N/A Citation: N/A Interpretive Summary: Chemical analysis plays a key role in protecting and evaluating our food supply. Traditional chemical analysis has involved the use of large quantities of noxious solvents that are injurious to laboratory personnel and to the environment. Studies at the National Center for Agricultural Utilization Research over the past ten years have investigated the use of high pressure gases, such as carbon dioxide as alternative solvents, due to their benign and versatile nature. Application of high pressure carbon dioxide and water for laboratory scale extractions of desired chemicals have been successfully applied for the determination of toxicants, nutrients, and minor contaminants in a variety of foods and agricultural products. High pressure carbon dioxide has proven particularly effective for the removal of fat from foods, thereby providing nutritional labeling information to the consumer. Such high pressure gas and liquid extractions offer the analyst a safe and more efficient sample treatment process that eliminates the use of dangerous and toxic liquid solvents traditionally used in these analytical protocols. Technical Abstract: Supercritical fluid (SF)-based analytical techniques and their resultant methods have provided an environmentally acceptable technology which minimizes the use of organic solvents in the chemical laboratory. Our laboratory has played a seminal role in conceptualizing and reducing to practice, CO2 based methods for trace pesticide analysis, the determination of nutrient content of foods, and the extraction of mycotoxins from a variety of sample matrices. Developmental efforts have benefitted in many cases from principles initially developed in the area of process SF technology; particularly in the application of supercritical fluid extraction (SFE) for fat analysis. This paper will trace the logic sequence which has guided the development of analytical SFE and its coupling with such techniques as sorbent trapping, SPR, enzyme immunoassay, and sample cleanup or chemical reactions sequenced with the extraction step. We have found that proper scaling of the extraction experiment as well as preparation of the sample matrix are critical to the success of SFE, and these aspects of SFE along with adjunct SF-based techniques, such as inverse SFE, size exclusion chromatography, and hyphenated variants SFE GC/SFE GC MS/SFE SFC, will be noted in this presentation. Finally, the status of SF based analytical techniques with respect to official methods, commercial instrumentation, and future research opportunities will conclude the lecture. |
