Quantitative analyses of methyl esters of fatty acid geometrical isomers, and of triglycerides differing in unsaturation, by the Iatroscan TLC/FID technique using AgNO3 impregnated rods

Lipids ◽  
1985 ◽  
Vol 20 (8) ◽  
pp. 555-560 ◽  
Author(s):  
J. L. Sebedio ◽  
T. E. Farquharson ◽  
R. G. Ackman
Keyword(s):  
Fatty Acid ◽  
Methyl Esters ◽  
Geometrical Isomers ◽  
Quantitative Analyses

scholarly journals Streamlined Methods for the Resolution and Quantification of Fatty Acids Including Trans Fatty Acid Isomers in Food Products by Gas Chromatography

2009 ◽  
Vol 92 (5) ◽  
pp. 1301-1309 ◽  
Author(s):  
Pierre-Alain Golay ◽  
Francesca Giuffrida ◽  
Fabiola Dionisi ◽  
Frédéric Destaillats
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
High Resolution ◽  
Methyl Esters ◽  
Direct Methods ◽  
Food Products ◽  
Response Factors ◽  
Geometrical Isomers ◽  
Cost Constraints ◽  
Wide Range

Abstract To support labeling, claims, and authenticity of food products, industry needs reliable methods for the analysis of fatty acids, including Trans fatty acids (TFA). In finished products, precise quantification of TFA can be problematic due to the occurrence of various positional and geometrical isomers originating from different sources, such as animal fats or processed vegetable oils and fats. The risk of underestimating TFA amounts is particularly high when inappropriate GC conditions are used. Complex sample preparation procedures involving purification of TFA isomers by silver ion chromatography have been well-documented and used for research purposes. However, in the food industry, time and cost constraints do not permit multiple analytical steps; therefore, streamlined methods are necessary. Direct methods include preparation of fatty acid methyl esters directly from food samples without prior extraction. The appropriate resolution is obtained using high-resolution GC with a highly polar 100 m capillary column, and quantification is achieved using experimentally determined response. We found that it is possible to quantify TFA in the range of 0.01 to 5.00 g/100 g of lipids in a wide range of food products. In addition, the use of direct transmethylation, response factors, and high-resolution GC allow accurate quantification of other fatty acids, including polyunsaturated and long-chain polyunsaturated fatty acids.

scholarly journals On the Combined Application of Iatroscan TLC-FID and GC-FID to Identify Total, Neutral, and Polar Lipids and Their Fatty Acids Extracted from Foods

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Vassilia J. Sinanoglou ◽  
Irini F. Strati ◽  
Sotirios M. Bratakos ◽  
Charalampos Proestos ◽  
Panagiotis Zoumpoulakis ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Polar Lipid ◽  
Methyl Esters ◽  
Fatty Acid Analysis ◽  
Lipid Classes ◽  
Geometrical Isomers ◽  
Detection Techniques ◽  
Combined Application ◽  
The Individual

An efficient separation and quantification of the individual neutral and polar lipid classes and their constituent fatty acids was achieved by the combination of two different detection techniques: Iatroscan TLC-FID and GC-FID. The solvent composition and ratio of development system, the sample size, the fidelity, and precision were tested in order to estimate the effectiveness of separation of individual neutral and polar lipid classes and the quantitative reproducibility of the Iatroscan TLC-FID technique. GC-FID method, with a high-quality capillary column, allowed sensitive and reproducible fatty acid qualitative and quantitative analyses, separation of fatty acid structural isomers (e.g., n-C16:0, iso-C16:0 and anteiso-C16:0), positional isomers (e.g., C18:1ω-9 and C18:1ω-7), geometrical isomers (cis-trans), and homologues (e.g., C16:0, C17:0, C18:0, etc.) in standards and complex lipid samples. Seventeen (17) lipid classes and fifty-two (52) saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids were identified and quantified, respectively, in samples of standard lipid and fatty acid mixtures, simulating the composition of natural lipids and their fatty acid methyl esters in common foods. The wide number of applications establishes this combination of Iatroscan TLC-FID and GC-FID methods as a powerful tool for lipid class and fatty acid analysis of any fat origin.

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