is dissolved in acetic acid and estimated 

 colorimetrically by the Liebermann-Bur- 

 chard reaction. Values by this method are 

 similar to those obtained with digitonin . 



Sorrel, M. F. and R. Reiser 



1957. Identification of some marine oil 

 constituents by chromatography. Jour- 

 ■^ nal of the American Oil Chemists Soci- 



ety, 34: 131-134. 

 Marine oils were separated into fractions 

 on a silicic acid column and the fractions 

 were further separated by chromatography 

 on silicic acid-impregnated paper. Rj 

 values of several components are given. 



Soyenkoff, B. G. 



1952. An improved micromethod of phos- 

 phate determination. Journal of Biolog - 

 ^ ical Chemistry, 198: 221-227. 



A modification of the method of Soyenkoff 

 (Journal of Biological Chemistry, 168 : 447, 

 1947) which eliminates many interferences. 



2-p-dimethylaminostyrylquinoline etho- 

 sulfate and ammonium molybdate are added 

 to the digested samples and the resulting 

 color is measured colorimetrically. Sen- 

 sitivity of the method is about 15 times that 

 of the Fiske-Subbarow method. Accuracy 

 with serum filtrates is 2%. 



Sperry, W. M. and R. Schoenheimer 



1935. A comparison of serum, heparin- 

 ized plasma, and oxalated plasma in 

 ■ regard to cholesterol content. Journal 



of Biological Chemistry , 110 : 655-658. 

 The content of total and free cholesterol 

 in oxalated blood plasma was found to be 

 lower than in serum or heparinized plasma 

 from the same blood sample. Cholesterol 

 content of serum and heparinized plasma 

 was the same. 



Sperry, W. M, 



1942. Electrophotometric microdeter- 

 mination of phosphorus in lipide ex- 

 tracts. Industrial and Engineering 

 Chemistry, Analytical Edition, 14: 88- 

 90. ~ 



A method is described for the determina- 

 tion of 2 to 25 ug. of lipid phosphorus using 

 reduced concentrations of the Fiske- 



Subbarow reagents and spectrophotometric 

 measurement at about 400 m u. Reagent 

 concentrations and temperature are not 

 critical. Recovery of added phosphorus is 

 quantitative. 



Sperry, W. M. and F. C. Brand 



1943. The colorimetric determination of 

 cholesterol . Journal of Biological Chem- 



" istry, 150: 315-324. 



A method for the determination of total 

 cholesterol using the Liebermann-Burchard 

 color reaction. Time of development and 

 temperature are critical . Saponification 

 with KOH is necessary, as esterified cho- 

 lesterol develops a stronger color faster 

 than free cholesterol. 



Sperry, W . M . and M . Webb 



1950. A revision of the Schoenheimer- 

 Sperry method for cholesterol deter - 

 ■ mination . Journal of Biological Chem- 



istry, 187: 97-110. 

 Dilute (50%) alcoholic solution of digitonin 

 was found to be preferable to aqueous solu- 

 tions of digitonin, as the aqueous solutions 

 may lose the ability to quantitatively precip- 

 itate cholesterol as they age. Precipitation 

 of the digitonide is net complete in 3 hours 

 at 37° . The precipitation appears to be in- 

 dependent of the amount of cholesterol pres- 

 ent in normal sera. Recovery of 99-101% 

 was obtained. 



Sperry, W. M. 



1954. _ A method for the determination of 

 total lipids and water in brain tissue. 

 # Journal of Biological Chemistry , 209: 



377-386. 

 Tissue is homogenized and an aliquot of 

 the homogenate is weighed. Water is ex- 

 tracted with acetone and evaporated, and the 

 tissue is dried to constant weight in a desic- 

 cator . Difference in tissue weight = water 

 removed. Lipids are extracted and. washed 

 according to Folch, et al (Journal of Biolog- 

 ical Chemistry, 191: 833, 1951) and weighed. 



TTiis method for determination of water 

 avoids errors from high temperature dry- 

 ing. 



65 



