Wycoff, H. D. and J. Parsons 



1957. Chromatographic microassay of 



"A" cholesterol and cholesterol esters. 



■ Science, 125 : 347-348. 



Free and esterified cholesterol are sep- 

 arated from about 0.02 ml. of plasma by 

 chromatography on SiOo, and estimated by 

 measurement of the color produced with 

 FeCl3 reagent. 



Yasuda, M. 



1931. Contributions to the micro deter- 

 mination of cholesterol. Journal of Bio - 

 logical Chemistry, 92: 303-312. 

 Modifications of Okey's procedure ( Jour- 

 nal of Biological Chemistry, 88: 367, 1930). 

 Acetone is used to separate the digitonide 

 from excess digitonin and lipid material. 

 The digitonide is freed of impurities by so- 

 lution in hot absolute alcohol and filtration. 



Yasuda, M. 



1931-2. The determination of the iodine 

 _ number of lipids . Journal of Biological 



* Chemistry, 94: 401-409. 



The lipids are halogenated with pyridine 

 sulfate dibromide, and the excess halogen 

 is titrated with thiosulfate. The method is 

 combined with determination of total lipid 

 by Bloor's oxidative procedure. Chloroform 

 dissolves the phospholipid precipitated from 

 acetone-MgCl2 as well as moist ether, and 

 dissolves a smaller amount of the MgCl2. 



Young, L . 



1934. The determination of inositol in 

 animal tissues. Biochemical Journal , 

 28: 1435-1443. 

 Inositol is extracted from tissue with 

 aqueous acetone, purified by precipitation, 

 and estimated by oxidation with potassium 

 iodomercurate. 



Youngs, C. G. andB. M. Craig 



1951. A note on the preparation of methyl 

 esters of fatty acids . Journal of the 

 _ American Oil Chemists Society^ 28: 



• 521-522. Chemical Abstracts, 46: 

 1271f (1952). 



A method is described for direct conver- 

 sion of saponified fatty acids to their methyl 

 esters with dimethyl sulfate. Yield is over 

 99%. 



Youngs, C. G., A. Epp, B. M. Craig, and 

 H. R. Sallans 



1957. Preparation of long-chain fatty 



acid chlorides. Journal of the American 

 • Oil Chemists Society, 34: 107-108. 



Chemical Abstracts, 51^:7039d (1957). 

 A method is described for preparation of 

 fatty acid chlorides by treating the free acid 

 with PCI5 or PCI3 in an inert organic solvent. 

 Excess chlorinating agent is removed by 

 washing the solvent phase with water. Yield 

 is quantitative, with less than 1 .5% of free 

 acid unreacted. 



Zak, B., R. C. Dickenham, E.G. White, 

 H. Burnett, and P. J. Chemey 



1954. Rapid estimation of free and total 

 cholesterol. American Journal of Clin - 

 ical Pathology, 24: 1307-1315. 

 Cholesterol is extracted from serum with 

 50:50 alcohol -acetone. Total cholesterol 

 is determined directly on the dried residue 

 of an aliquot of the extract, and free choles- 

 terol is precipitated with digitonin in another 

 aliquot. Color is developed in both portions 

 with the FeCl3 -acetic acid reagent of Zlatkis, 

 et al ( Journal of Laboratory and Clinical 

 Medicine, 41: 486, 1953). 



Zak, B., N. Moss, A. J. Boyle, and A. Zlatkis 

 1954. Reactions of certain unsaturated 

 sterols with acid iron reagent. Ana- 

 lytical Chemistry, 26: 776-777. 

 Colors produced by reaction of various 

 sterols with ferric chloride -acetic acid- 

 sulfuric acid reagent are given. 



Zak, B. 



1957. Simple rapid microtechnic for 

 serum total cholesterol. American 



■ Journal of Clinical Pathology, 27: 583- 



588. 

 Serum proteins are precipitated with a 

 ferric chloride -acetic acid solution. A por- 

 tion of the supernatant is diluted with H2SO4 

 and the resulting color is measured in a 

 spectrophotometer at 560 mu. 



Zbinovsky, V. 



1955. New solvent for separating mono - 

 ir carboxylic acids (C2 to C^^) and dicar- 



# boxylic acids (C2 to 022)- Analytical 



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