STUDIES OF AERATION METHODS FOR THE DE- 

 TERMINATION OF AMMONIUM NITROGEN 



3. The ammonium nitrogen in beef* 



JACOB SHULANSKY and WILLIAM J. GIES 



{Biochemical Laboratory of Columbia University, at the College of Physicians 



and Surgeons, New York) 



I. Introduction. A modification of the original Folin 

 METHOD. Several years ago, during the course of a series of €x- 

 periments on the effects of magnesium sulfate on metabolism, Steel^ 

 obtained anomalous results with the Polin method for the determi- 

 nation of urinary ammonium. The senior author, who was directing 

 the experiments, suggested that these anomalous results might be 

 due to the formation of ammonio-magnesium phosphate and to in- 

 complete ejection, by the Folin method, of the ammonium from this 

 Compound. With Steel,^ he then ascertained that the Folin method 

 was inadequate for the determination of the yield of ammonia from 

 urine that contained crystalline ammonio-magnesium phosphate. 

 They found that sodium carbonate, in the proportions employed 

 for the Folin method, was unable to disengage more than about 40 

 percent of the ammonium nitrogen from moderate quantities of 

 ammonio-magnesium phosphate, whereas 0.5-1 gram of caustic 

 alkali (instead of carbonate) promptly ejected all of it from large 

 amounts of such phosphate. " Even in the presence of 50 times its 

 weight of sodium carbonate and with 10 hours of thorough aeration, 

 crystalline ammonio-magnesium phosphate cannot be completely 

 decomposed by the Folin method of ammonia determination" (p. 

 81). Steel and Gies wrote as follows at the conclusion of their 

 paper : " We hope in the near f uture to report a simple modification 



* The previous papers in this series were those by (i) Steel and Gies: Jour. 

 Biol. Chem., 1908, v, p. 71, and (2) Steel: Ibid., 1910, viii, p. 365. 



1 Steel : Ibid., 1908, v, p. 85. (Dissertation submitted in partial fulfilment of 

 the requirements for the degree of Ph.D. at Columbia University.) 



2 Steel and Gies: Ibid., 1908, v, p. 71. 



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