Methods for the determination of cyclopropenoid fatty acids. II. A stepwise hydrogen bromide titration method for cyclopropenid and epoxy derivatives

Abstract An evaluation of 5 methods for determining 5% or less cyclopropenoid fatty acids was made in terms of accuracy, precision, and sensitivity. GLC of the methyl mercaptan derivatives of cyclopropenoid fatty acids and titration with hydrobromic acid in toluene were found to be unsuitable. GLC of the silver nitratemethanol derivatives (quantitation by an internal standard) and titration with hydrobromic acid in acetic acid were equally precise, and the former required less sample; however, both methods gave low recoveries. GLC of silver nitrate-methanol derivatives (quantitation by peak area normalization) and a hydrobromic acid-benzene back-titration method gave good recoveries. The Halphen test was found to be the best general method when calibrated with a cyclopropenoid fatty acid standard analyzed by the silver nitrate-methanol GLC method (quantitation by peak area normalization) or the hydrobromic acid-benzene back-titration method.

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An Extraction-Titration Method for the Determination of Free Fatty Acids in Rancid Milk and Cream

Journal of Dairy Science ◽

10.3168/jds.s0022-0302(55)95036-0 ◽

1955 ◽

Vol 38 (7) ◽

pp. 751-763 ◽

Cited By ~ 30

Author(s):

E.N. Frankel ◽

N.P. Tarassuk

Keyword(s):

Fatty Acids ◽

Free Fatty Acids ◽

Titration Method

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A modified two-point titration method for the determination of volatile fatty acids in anaerobic systems

Chemosphere ◽

10.1016/j.chemosphere.2018.04.038 ◽

2018 ◽

Vol 204 ◽

pp. 251-256 ◽

Cited By ~ 2

Author(s):

Zhe-Xuan Mu ◽

Chuan-Shu He ◽

Jian-Kai Jiang ◽

Jie Zhang ◽

Hou-Yun Yang ◽

...

Keyword(s):

Fatty Acids ◽

Volatile Fatty Acids ◽

Titration Method

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Determination of Cyclopropenoid Fatty Acids in Ewe Milk Fat by GC-MS after Intravenous Administration of Sterculic Acid

Foods ◽

10.3390/foods9070901 ◽

2020 ◽

Vol 9 (7) ◽

pp. 901

Author(s):

Veronica Lolli ◽

Pablo G. Toral ◽

Augusta Caligiani ◽

Pilar Gómez-Cortés

Keyword(s):

Fatty Acids ◽

Milk Fat ◽

Sterculic Acid ◽

Bioactive Lipids ◽

Cyclopropenoid Fatty Acids ◽

Δ9 Desaturase ◽

First Time ◽

Endogenous Synthesis

Cyclopropenoid fatty acids (CPEFA), found in oilseeds from Malvaceae and Sterculiaceae, have been shown to interfere with the endogenous synthesis of several bioactive lipids of dairy fat, such as cis-9, trans-11 18:2 and cis-9 18:1, by inhibiting Δ9-desaturase. No previous study has reported the presence of sterculic acid in animal fat and its incorporation in tissues after its administration, due to the lack of a proper methodology. In the present research, a GC-MS method based on cold base derivatization to fatty acids methylesters was developed to determine CPEFA in ewe milk triglycerides, after infusing sterculic acid (0.5 g/day) to six lactating ewes. An alternative derivatization based on silanyzation followed by GC-MS analysis was also tested, showing its possible applicability when CPEFA are present in the form of free fatty acids. Sterculic acid was detected in ewe milk triglycerides, demonstrating its incorporation from the bloodstream into milk by the mammary gland. The mean transfer rate represented 8.0 ± 1.0% of the daily dose. This study provides, for the first time, the presence of sterculic acid in milk fat, supporting the importance of understanding its occurrence in vivo and encouraging further research to determine whether it can be present in foods, such as dairy products, obtained under practical farming conditions.

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A Comparison of Gas-Liquid Chromatography and a Titration Method for the Determination of Plasma Non-Esterified Fatty Acid Levels during Pregnancy

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/000456327501200165 ◽

1975 ◽

Vol 12 (1-6) ◽

pp. 249-251 ◽

Cited By ~ 1

Author(s):

Maureen Young ◽

Elizabeth A. Gilmore ◽

R. G. McDonald-Gibson ◽

Jennifer A. Elliott

Keyword(s):

Fatty Acids ◽

Liquid Chromatography ◽

Fatty Acid ◽

Post Partum ◽

Gas Liquid Chromatography ◽

Plasma Nefa ◽

Titration Method ◽

Esterified Fatty Acids ◽

Nefa Level

The level of plasma non-esterified fatty acids (NEFA) was measured by gas-liquid chromatography (GLC) and a titration method in 194 samples collected during pregnancy and from four days to 24 weeks post partum. Both techniques indicated a similar pattern of changes in plasma NEFA associated with pregnancy. The titration estimates of NEFA level were usually greater than those measured by GLC, and there was some suggestion that the disparity between the methods was increased at the end of pregnancy and was reduced at six weeks after delivery.

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710. The determination of free fatty acids in milk

Journal of Dairy Research ◽

10.1017/s0022029900009225 ◽

1958 ◽

Vol 25 (2) ◽

pp. 221-227 ◽

Cited By ~ 11

Author(s):

Dawn R. Perrin ◽

D. D. Perrin

Keyword(s):

Fatty Acids ◽

Molecular Weight ◽

Free Fatty Acids ◽

Milk Fat ◽

Small Samples ◽

Titration Method ◽

Fresh Milk ◽

Lactic Acids ◽

Accurate Indicator

An extraction-titration method is described for the determination of free fatty acids in small samples of fresh milk.Recoveries of fatty acids added to milk ranged from 63% for butyric acid to 97% for stearic acid. For a composite sample approximating milk fat in fatty acid composition the recovery was 83%.Interference from citric and lactic acids was not significant for reasonably fresh samples.The method gives a higher recovery of the lower molecular weight fatty acids than is possible by earlier methods.For titrating very dilute solutions of fatty acids α-naphtholphthalein was shown to be a more accurate indicator than phenolphthalein; it also provides a better defined endpoint.

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