A method for the quantitative determination of individual free fatty acids in milk by ion exchange resin adsorption and gas-liquid chromatography

1983 ◽  
Vol 50 (3) ◽  
pp. 321-329 ◽  
Author(s):  
Eric C. Needs ◽  
Graeme D. Ford ◽  
A. Jane Owen ◽  
Brian Tuckley ◽  
Malcolm Anderson
Keyword(s):  
Fatty Acids ◽  
Liquid Chromatography ◽  
Free Fatty Acids ◽  
Exchange Resin ◽  
Ion Exchange Resin ◽  
Gas Liquid Chromatography ◽  
Internal Standards ◽  
Resin Adsorption ◽  
The Individual

SummaryA quantitative method for rapid routine analysis of individual free fatty acids (FFA) in milk was developed. Lipid was extracted from milk in ether and FFA were recovered by shaking the extract with anion exchange resin Amberlyst 26. The resin-bound FFA were methylated directly and the individual acids quantified, using internal standards, by gas-liquid chromatography. The properties of the resin were measured. The validity of the method was established by extraction of FFA mixtures and milk. Individual acids were, on average, found to be within 6% of the actual concentration present in the mixture. An average coefficient of variation of 4·3% was achieved for the major individual fatty acids on repeated extraction of a single milk sample.

scholarly journals Gas Chromatographic Determination of Traces of Accelerants in Physical Evidence

1972 ◽  
Vol 55 (4) ◽  
pp. 840-845 ◽  
Author(s):  
Charles R Midkiff ◽  
Willard D Washington
Keyword(s):  
Liquid Chromatography ◽  
Solvent Extraction ◽  
Vapor Phase ◽  
Selection Criteria ◽  
Chromatographic Determination ◽  
Operating Parameters ◽  
Gas Liquid Chromatography ◽  
Internal Standards ◽  
Physical Evidence

Techniques developed for use with gas-liquid chromatography for the examination of evidence collected at the scene of suspected arson fires and firebombings are discussed. Both solvent extraction and vapor phase examinations are employed. Internal standards are used for the identification of specific components in actual samples to allow confirmation of hydrocarbon type, e.g., gasoline and kerosene. Operating parameters and solvent selection criteria are included. Results obtained from known materials and residual hydrocarbons in actual samples are compared.

Ozonolysis of unsaturated fatty acids. II. Esterification of the total products from the oxidative decomposition of ozonides with 2,2-dimethoxypropane

1967 ◽  
Vol 45 (13) ◽  
pp. 1405-1410 ◽  
Author(s):  
John D. Castell ◽  
R. G. Ackman
Keyword(s):  
Fatty Acids ◽  
Liquid Chromatography ◽  
Unsaturated Fatty Acids ◽  
Performic Acid ◽  
Acid Oxidation ◽  
Gas Liquid Chromatography ◽  
Positional Isomers ◽  
Flame Ionization ◽  
Hydrogen Flame

The total acidic products from the performic acid oxidation of the ozonide of methyl oleate formed in methanol may be esterified directly in a few hours with 2,2-dimethoxypropane. The ester concentrations are adequate for the determination of the positional isomers of monoethylenic fatty acids directly from the reaction mixture, using a hydrogen flame ionization gas–liquid chromatography detector. Dimethyl sulfoxide was not required to prevent the breakdown of 2,2-dimethoxypropane under the conditions employed.

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