Submitted to: Laboratory Automation Robotics International Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 10/22/1997
Publication Date: N/A
Technical Abstract: Our studies on the absorption and metabolism of triglyceride (TG) positional isomers in human and animal models required the analysis of isolated triglyceride samples by lipase. The triglycerides of blood and isolated blood fractions, mouse liver tissue, native/randomized lard and soybean oil were extracted and treated with lipase. The 2-monoglyceride (MG) fractions were separated from TGs and diglycerides (DGs) on a Zymark Benchmate Workstation by silica SPE (3 mL Bond Elute columns). TLC was used to verify the completeness of MG separation. Average recoveries (ca. 40%) of the 2-monoglycerides in >95 purity were consistent with published results. The isolated MGs were manually converted to methyl esters and the Workstation (hexane as extracting solvent) was used to isolate the methyl ester fractions from the reaction mixtures. The impact(s) of solvent volumes, mixing times and sample sizes on MG and ester recoveries was studied. Gas chromatography was used to determine fatty acid compositions; % recoveries were calculated by the addition of known weights of 17:0 and 21:0 internal standards to the samples. Ester recoveries for the Zymark were dependent on the initial substrates and varied from 65 to >90% compared to manual extraction data. Fatty acid compositions of ester samples isolated by robotic methods agreed within 0.5% with samples isolated by non-robotic means. Oxidation products were not a problem. Solvent removal from the isolated samples was done on a Zymark TurboVap LV Evaporator.