ISSN:
0935-6304
Keywords:
Capillary gas chromatography
;
Solid-phase clean-up
;
Free fatty acids (C2-C20)
;
Quantification/repeatability
;
Dairy products
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A rapid, reliable and precise capillary gas chromatographic method for routine quantification of short- and long-chain free fatty acids (FFA) in milk and cheese is described. Procedures of (1) lipid extraction, (2) isolation of the FFA from milk and cheese extracts, and (3) capillary gas chromatographic analysis were developed and optimized. FFA can be extracted from cheese for 95-100% with ether-heptane after grinding with sodium sulfate and addition of 2.5 M sulfuric acid. From milk, 95-100 % of the FFA (≤ C8:0) are also extracted with ether-heptane after addition of ethanol and 2.5 M sulfuric acid. Internal standards are used to compensate for the losses of lower FFA (C2:0-C8:0) in the aqueous phase. In view of the excellent recovery (98-100 %) and a considerable saving of time, the use of an aminopropyl column is preferred for the isolation of the FFA from lipid-extracts. The underivatized FFA are separated directly by capillary gas chromatography making use of columns which enable accurate and rapid (≤ 40 min) determination of FFA C2:0-C20:0. With the method described, all major FFA (C2:0-C18:3) in milk and cheese can be quantified with good repeatability (rsd less then 2 %). The method is also applicable to the analysis of short-chain fatty acids in other products.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jhrc.1240130204
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