cholesterol by the ferric chloride method 

 of Zlatkis, Zak, and Boyle ( Journal of Lab- 

 oratory and Clinical Medicine, 41 : 486, 

 1953). Color yields, expressed as percent- 

 ages of cholesterol value, varied from 0.047 

 to 6.5%. 



method of Herb and Riemenschneider ( Ana - 

 lytical Chemistry, 25: 953, 1953) for deter- 

 mination of the fatty acid composition of 

 0.5 to 2 ml. of plasma or- of the fractions 

 from a chromatographed (Si02) sample of 

 tissue lipids. 



• 



A 



Rice, E. W. and D. B. Lukasiewicz 



1957. Influence of bromine in the Zak 

 cholesterol method. Clinical Chem- 



" istry, 3: 160-162. 



Traces of Br will give high values in the 

 FeCl3-H2S04 color reaction for cholesterol. 

 Shaking the serum with Agl03 before extrac- 

 tion with ethanol-dimethyl ketone will elim- 

 inate the Br interference. 



Rice, F . A . H . and A . G . Osier 



1951. Chromatographic purification and 

 serologic studies of a beef heart leci- 

 thin . Journal of Biological Chemistry , 

 189 : 115-121. 

 A method is described for the purification 

 of lecithin for use in sero-diagnosis of syph- 

 ilis. The lecithin is adsorbed on a "Mag- 

 nesol" (hydrated magnesium acid silioate)- 

 Celite column and eluted with 2% tertiary - 

 butyl alcohol in benzene . 



Riemenschneider, R. W., S. F. Herb, and 

 P. L. Nichols, Jr. 



1949. Isolation of pure natural linoleic 

 acid and linolenic acids as their methyl 

 j^ esters by adsorption fractionation on 



^ silicic acid. Journal of the American 



• Oil Chemists Society, 26: 371-374. 

 Chemical Abstracts, 43:68391(1949). 



The methyl esters were prepared from 

 linoleic and linolenic acids from tobacco 

 oil and linseed oil, respectively, and chro- 

 matographed on silicic acid-Celite with pe- 

 troleum ether and petroleum ether methyl 

 ether. 



Riemenschneider, R. W., F. E. Luddy, and 

 S. G. Morris 



1958. Determination of fatty acids in 

 small amounts of plasma and in lipid 

 components of tissues by ultraviolet 



* spectroscopy. American Journal of 

 CUnical Nutrition, 6: 587-591. 



An adaptation of the spectrophotometric 



Rigamonti, R . and V . Ricco 



1954. Separation of fatty acids of differ- 

 ent molecular weight by means of addi- 



^ tion compounds with urea. Annali di 



Chimica (Rome)44: 288-298. 

 Fatty acids of 90% purity may be separa- 

 ted from fatty acid mixtures by fractional 

 precipitation of their urea complexes. 



Rikimaru, M., Y. Tanaka, andM. Hoshino 



1955. Paper chromatography of phospho- 

 lipides. Fukushima Journal of Medical 

 Science, 2: 131-133. Chemical Ab- 



• 



stracts, 50:13156d(1956). 

 A study of solvents suitable for the paper 

 chromatography of lecithins and lysolecithin . 

 Best results were obtained with a butanol- 

 glycerol -water mixture. 



Rikimaru, M. 



1955. Chromatographic separation of 

 lecithin and lysolecithin on silica - 

 ■^ treated filter paper disk. Fukushima 



▲ Journal of Medical Science, 2: 175-177. 



Chemical Abstracts, 50:13147g (1956). 

 Lecithin and lysolecithin were separated 

 on silica -impregnated filter paper using 

 CHCl3-MeOH or CHCl3-EtOH as developing 

 solvents. TTie bands were located with phos- 

 phomolybdic acid. Rj values are given. 



Roberts, H. R. andW. Bucek 



1957. Rapid procedure for separation of 

 C2 to C6 volatile fatty acids by hori- 

 ■^ zontal paper chromatography at elevated 



^ temperature . Analytical Chemistry, 



29: 1447-1449. 

 The C2 to C6 fatty acids were separated 

 by horizontal paper chromatography of their 

 ethylamine salts using butanol saturated 

 with water as solvent and a temperature of 

 50° for development. 



Roberts, W . L . and H . A . Schuette 



1932 . Determination of hydroxyl number 



58 



