DEVELOPMENT OF AN AUTOMATED SFE/SFR/GC PROCEDURE FOR THE ANALYSIS OF TOTAL FAT CONTENT OF FOODS

Authors: Snyder, Janet; KING, JERRY; Vorhauer, Jacquelyn

Submitted to: International Symposium on Hyphenated Techniques in Chromatography
Publication Type: Abstract Only
Publication Acceptance Date: 2/9/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Regulatory changes in the definition of the total fat content of food in the United States has accelerated the development of new techniques that eliminate the use of organic solvents. Our research group has been involved in a systematic program to integrate supercritical fluid extraction (SFE) into new analytical protocols for the analysis of nutrients and the determination of total, saturated, and monounsaturated fat in meat products. The development of this hyphenated method depends on the use of a non-specific lipase catalyst inserted in-line after the SFE step for hydrolysis of the extracted triglycerides. A hydrolase catalyst (1 g) and 1 g sample were used with the conditions of 17.2 MPA and 50 deg C to permit simultaneous hydrolysis and conversion to fatty acid methyl esters for GC analysis during SFE. The enzyme has been reused over 25 times and has retained its activity. Enzymatic conversion of the extracted triglycerides has been monitored off-line by supercritical fluid chromatography and shown to be complete. The method was automated using a Hewlett Packard Model SFE unit, in tandem with a bridge" system, connected on-line with a GC. The resultant derivatized extract is collected in a standard GC injection vial, transferred by the robotic arm of the autosampler on the GC to the GC sample tray, and subsequently injected for analysis on the GC using a capillary column. Excellent data have been achieved to date using the above hyphenated system, which provides for the analyst an integrated sample hydrolysis, extraction, derivatization, and analysis protocol.