VII. ESTIMATION OF INOSITOL 359 



et al.^). The Scherer test has recently been discussed in some detail by 

 Fleury.^ 



The introduction of the use of 70 % acetone for the extraction of inositoF 

 improved the isolation procedure. Estimation by isolation and weighing 

 remains, however, a very crude method for inositol determination. 



B. BY CHEMICAL METHODS 



ARTHUR H. LIVERMORE 



The introduction of chemical methods for the estimation of inositol was 

 some improvement over the earlier procedures. However, considerable 

 purification of the inositol to remove interfering substances was still re- 

 quired. 



1. Reaction with Potassium Iodomercurate* ■ ^ 



Potassium iodomercurate in alkaline solution is reduced to free mercury 

 by inositol and also by sugars. The mercury can then be dissolved in a 

 measured excess of a standard iodine solution and the unreacted iodine 

 determined by titration with thiosulfate. 



2. Reaction with Periodate 



The most satisfactory chemical method for determining inositol is to 

 oxidize it with periodate.^' ^"'^^ In the method of Piatt and Glock,^" the 

 inositol must first be extracted from tissues with boiling water and im- 

 purities removed by precipitating some with 70% acetone and extracting 

 others with ether. Glucose can be destroyed by fermentation with yeast, 

 and then lactic acid and other interfering substances can be removed by 

 adsorption on carbonaceous zeolite and M.P.D. resin. 



The inositol solution obtained in this fashion is treated with HIO4 at 

 6° to 8° for 48 hours, at which time the theoretical amount of HIO4 required 

 by equation 1 is used up. The formic acid produced is then titrated with 



C6H6(OH)6 + 6HIO4 ^ 6HIO3 + 6HC00H (1) 



0.01 N NaOH. Piatt and Glock found that, when the theoretical amount 

 of HIO4 had reacted, 90% of the theoretical amount of formic acid was 

 present in the solution. 



6 H. H. Hutt, T. Malkin, A. G. Poole, and P. R. Watt, Nature 165, 314 (1950) 

 «P. Fleury, Bull. soc. chim. biol. 33, 1061 (1951). 

 ^ G. Momose, Biochem. J. (London) 10, 120 (1916). 

 8 P. Fleury and J. Marque, J. pharm. chim. [8] 10, 241 (1929). 

 "L. Young, Biochem. J. (London) 28, 1435 (1934). 

 " B. S. Piatt and G. E. Glock, Biochem. J. (London) 37, 709 (1943). 

 " P. Gyorgy, Vitamin Methods, p. 252, Academic Press, New York, 1950. 

 12 P. Fleury and M. Joly, J. pharm. chim. [8] 26, 341, 397 (1937). 



