stracts , 37: 3119^(1943). 

 The cholesterol is extracted from plasma 

 with EtOH -petroleum ether (2:3), and the 

 extract is dried and evaporated. The resi- 

 due is dissolved in CCI4 and chromato- 

 graphed on an AI2O2 column. Esterified 

 cholesterol is eluted with CCl^ and free 

 cholesterol with CHCI3, and cholesterol 

 content of each fraction is estimated color- 

 imetrically using ZnCl2-AcOH and AcCl. 



Trinder, P. 



1952. Determination of cholesterol in 



■ serum. Analyst, 77 : 321-325. 

 Cholesterol esters are hydrolyzed by 



heating the serum with alcoholic KOH, and 

 the cholesterol is extracted with petroleum 

 ether. Color is developed with acetyl 

 chloride -sulfuric acid. 



Trusov, V. I. 



1950. Determination of choline in biolog- 

 ical materials. Biokhimiya, 15 : 495- 

 498. Chemical Abstracts, 45:3448f 

 (1951). 

 Choline is precipitated as the reineckate, 

 the Cr is oxidized by KBrOg or H2O2, and 

 the resulting chromate is titrated with 

 Na2S203 . 



Turner, M. E. 



1931 . A simplification of the Okey meth- 

 od for the determination of cholesterol 



■ by the oxidation of the digitonide . Jour 

 nal of Biological Chemistry , 92: 495-498. 



A modification of the Okey method (Journal 

 of Biological Chemistry , 88: 367, 1930) for 

 oxidation of cholesterol digitonide. 



Twltchell, E. 



1921. The precipitation of solid fatty 

 , acids with lead acetate in alcoholic so- 



^ lution. Journal of Industrial and Engi- 



* neering Chemistry, 13: 806-807. 



A method is described for separation of 

 the liquid and solid fatty acids in which the 

 solid acids are precipitated from a hot al- 

 coholic solution by addition of lead acetate 

 and cooling. The liquid acids remain in 

 solution and are filtered off. 



Uzman, L. L. 



1953 . A general method for the prepara- 

 tion of cerebrosides. Archives of Bio- 

 chemistry and Biophysics, 45 : 149-155. 

 Tissue is homogenized and extracted with 

 CHCl3-MeOH (2:1) and trichloracetic acid 

 is added. The mixture is centrifuged, the 

 upper and lower layers of the three-phase 

 system are drawn off, and the interphase 

 layer is dialyzed against distilled water. 

 The resulting material is recrystallized 

 from alcohol-chloroform (1:1). 65-75% of 

 the total tissue cerebrosides are obtained 

 from spleen and brain . 



Van Beers, G. J., H. De longh, and J. Boldingh 

 1957. Isolation of phospholipides by 

 dialysis through a rubber membrane. 

 Essential Fatty Acids. Proceedings of 

 '^ the International Conference on Biochem - 



A ical Problems of Lipids, 4th Oxford, 



(Pub. 1958) pp. 43-47. Chemical Ab- 

 stracts, 53:17278a (1959). 

 A method is described for separation of 

 phospholipids from lipid mixtures by dialy- 

 sis through a rubber membrane. The phos- 

 pholipids do not pass through when a non- 

 polar solvent is used. 



Van de Kamer, J. H., N. A. Pikaar, 



A. Bolsaens-Frankena, C. Couvee-Pioeg, 

 and L. van Ginkel 



1955. Quantitative determination of the 

 different higher saturated fatty acids 



. in fat from blood, chyle, and faeces, 



by means of partition chromatography 



* on rubber. Biochemical Journal, 61: 

 180-186. ~ 



The fats are extracted and saponified, and 

 the fatty acids are extracted from the hydrol- 

 ysate. The unsaturated fatty acids are oxi- 

 dized with KMn04, and the saturated fatty 

 acids are separated on a rubber chromato- 

 graphic column with acetone -water solvent 

 mixtures . 



Vandenheuvel, F. A. and D. R. Vatcher 



1956. Partition chromatography of ali- 

 phatic acids. Quantitative resolution 



^ on normal chain even acids from Cj^2 



# to C24. Analytical Chemistry , 28: 838- 

 845. 



71 



