THE TITRIMETRIC DETERMINATION OF PLASMA FATTY ACIDS

1951 ◽  
Vol 29 (5) ◽  
pp. 239-244
Author(s):  
Edouard Pagé ◽  
Loraine Michaud
Keyword(s):  
Fatty Acids ◽  
Blood Plasma ◽  
Plasma Lipids ◽  
Benzene Solution ◽  
Ammonium Hydroxide ◽  
Thymol Blue ◽  
Tetramethyl Ammonium Hydroxide ◽  
Total Fatty Acids ◽  
Titrimetric Determination

A method is described for the determination of total fatty acids in small amounts of blood plasma. The plasma lipids are extracted in an alcohol–acetone mixture. Following saponification and hydrolysis, the fatty acids from an aliquot of their benzene solution are dissolved in alcoholic thymol blue and titrated with tetramethyl ammonium hydroxide as recommended by Schmidt–Nielsen. The method is applicable to the study of alimentary hyperlipemia in rats.

THE INTERRELATION OF LIPIDS IN THE BLOOD PLASMA OF WHITE LEGHORN COCKERELS

1940 ◽  
Vol 18d (2) ◽  
pp. 49-52 ◽  
Author(s):  
Eldon M. Boyd ◽  
Eleanor L. Clarke
Keyword(s):  
Fatty Acids ◽  
Blood Plasma ◽  
Total Cholesterol ◽  
Total Lipid ◽  
Free Cholesterol ◽  
White Leghorn ◽  
Plasma Total Lipid ◽  
Total Fatty Acids

The blood plasma of 22 healthy, young, white leghorn cockerels was analysed by oxidative micromethods and found to contain the following mean lipid values, in milligrams per 100 ml. of plasma: total lipid 520, neutral fat 225, total fatty acids 361, total cholesterol 100, ester cholesterol 66, free cholesterol 34, phospholipid 155. In general, the amounts of the various lipids were proportionately related to the total lipid.

Liquid Chromatographic Determination of the Estrogens Daidzein, Formononetin, Coumestrol, and Equol in Bovine Blood Plasma and Urine

1988 ◽  
Vol 71 (5) ◽  
pp. 938-941 ◽  
Author(s):  
Torbjorn J O Lundh ◽  
Hans Pettersson ◽  
Karl-Heinz Kiessling
Keyword(s):  
Ethyl Acetate ◽  
Blood Plasma ◽  
Ammonium Hydroxide ◽  
Normal Diet ◽  
Urine Samples ◽  
Gradient System ◽  
Bovine Blood ◽  
Blood Samples ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method is described for the determination of the plant estrogens daidzein, formononetin, and coumestrol and the estrogenically active metabolite equol in bovine blood plasma and urine. The blood and urine samples are incubated overnight with and without β3-glucuronidase/sulfatase for analysis of both free and conjugated forms of estrogens. Samples are applied to Extrelut ® columns, extracted with ethyl acetate, and evaporated to dryness. Residues from urine samples are dissolved in methanol, diluted with water, acidified with HCl, and purified by injection through a Sep-Pak® C,8 cartridge. This eluate is used for LC analysis. Residues from blood samples are dissolved in benzene-petroleum ether (1 + 1), extracted with ammonium hydroxide, acidified with glacial acetic acid, and extracted with ethyl acetate. The ethyl acetate extract is evaporated, dissolved in 80% methanol, injected onto a LC reversephase column, and separated in a linear gradient system between 40 and 80% methanol in phosphate buffer. Quantitation is performed by means of UV and fluorescence responses. The method was sensitive enough to determine 0.4 μg/mL of daidzein and formononetin and 0.1 and 13 ng/mL of coumestrol and equol, respectively, in blood, and 130,80, and 7 ®g/mL of daidzein, formononetin, and coumestrol, respectively, and 4 Mg/mL of equol in urine. The applicability of the method was checked by the determination of total and free plant estrogens in blood samples from a dairy cow fed a normal diet.

Inductively Coupled Plasma-Mass Spectrometric Determination of Iodine in Food Using Tetramethyl Ammonium Hydroxide Extraction—Results from a U.S. Food and Drug Administration Level 3 Interlaboratory Study

2019 ◽  
Vol 102 (4) ◽  
pp. 1194-1198 ◽  
Author(s):  
Todor I Todorov ◽  
Yunseol Kim ◽  
Jennifer Fong Sam ◽  
Erica Mote ◽  
Cynthia C Smith ◽  
...  
Keyword(s):  
Drug Administration ◽  
Reference Materials ◽  
Inductively Coupled Plasma ◽  
Food And Drug Administration ◽  
Ammonium Hydroxide ◽  
Mass Spectrometric ◽  
Interlaboratory Study ◽  
Inductively Coupled ◽  
Tetramethyl Ammonium Hydroxide

Abstract Background: The performance of U.S. Food and Drug Administration (FDA) Elemental Analysis Manual (EAM) 4.13 method (Inductively Coupled Plasma-Mass Spectrometric Determination of Iodine in Food Using Tetramethyl Ammonium Hydroxide Extraction) was tested in an interlaboratory study. Objective: The aim of the study is to demonstrate that the FDA EAM method 4.13 is applicable for the analysis of food and multivitamins. Methods: Six collaborators participated in the study using four different models of inductively coupled plasma-mass spectrometry instruments. The method evaluation included determination of the limits of detection and quantification, analysis of National Institute of Standards and Technology standard reference materials (SRMs), unknown samples, blinded SRMs, and fortified analytical portions by all six collaborators. The samples were chosen to represent all sectors of the AOAC food triangle and additionally included pet food and multivitamin tablets. Results: The repeatability and reproducibility ranges were 1.8–11.4% and 3.6–13.7%, respectively; the calculated HorRat values were in the 0.17–1.18 range; and 174 of 175 SRM analyses had z-scores <2 and fortified analytical portion samples with recoveries of 102–105%, indicating acceptable method performance. Conclusions: The study supports a Level Three Multilaboratory Validation according to FDA Food and Veterinary Program Guidelines performed by six collaborators using six certified reference materials and nine unknown samples. Highlights: The method is applicable for quantification of the total extractable iodine in food and multivitamin dietary supplements.

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