SANITARY STUDIES OF BAKING POWDERS 



5. The determination of aluminium in biological material: a 



comparison of the method of Steel (modified by Kahn) 



with the method of Schmidt and Hoagland 



CLARENCE A. SMITH and PHILIP B. HAWK 



(Laborafory of Physiological Chemistry, Jefferson Medical College, Philadelphia) 

 (Received for publication, January 29, 1916) 



Introduction. As a preliminary to work concerning the ab- 

 sorption of aluminium, we compared the two methods which are 

 most used for the quantitative estimation of aluminium. These two 

 methods are the one proposed by Steel^ and modified by Kahn^; 

 and the method of Schmidt and Hoagland.^ 



Aluminium was determined by each method in (i) a water sol. 

 containing a known amount of alum, (2) a water sol. containing 

 a known amount of alum and different amounts of ferric chlorid, 

 (3) human gastric juice to which a known amount of a Standard 

 sol. of alum had been added (determination made directly without 

 evaporation and ashing), (4) human gastric juice evaporated and 

 ashed after the addition of a known amount of Standard alum sol., 

 and (5) beef blood to which a known amount of Standard alum 

 sol. had been added. 



We hoped to obtain a Standard sol. of an aluminium salt from the 

 U. S. Bureau of Standards, but this was found to be unavailable. 

 A pure preparation of alum (crystallized potassium aluminium Sul- 

 fate) was made by twice recrystallizing Baker's analyzed potassium 

 aluminium sulfate. In making the "Standard sol. of alum" used 

 throughout the experiment, 9.2863 gm. of the pure crystallized alum 

 were dissolved in dist. water and diluted to 500 cc. This sol. con- 



1 Steel, M. : Amer. Jour. Physiol., 1911, xxviii, p. 100. 



2 Kahn, Max: Biochem. Bull., 191 1, i, p. 237. 



3 Schmidt, C. L. A., and Hoagland, D. R. : Jour. Biol. Chem., 1912, xi, p. 437- 



183 



