CHAPTER XXVII 

 URINE: QUANTITATIVE ANALYSIS 



IN analyzing a normal or pathological urine quantitatively for 

 any of its constituents it is particularly necessary that the complete 

 and exact 24-hour sample be obtained. For directions with regard to 

 the collection and preservation of urine for analysis see Chapter 

 XXII on General Characteristics of Normal and Pathological Urine. 

 Methods for the determination of the specific gravity of the urine are 

 also there described. Before any urine is taken for analysis its total 

 volume should be measured, using a large graduated cylinder, and this 

 volume is thereafter taken as a basis for the calculations of the daily 

 output of the individual constituents determined. If the urine be 

 pathological it is of course necessary to precede its quantitative 

 analysis by qualitative tests for the pathological constituents. 



PREPARATION OF STANDARD ACID AND ALKALI SOLUTIONS 



Principle. Many of the quantitative methods used in physiological 

 chemistry are volumetric or titration procedures. For these methods 

 solutions of accurately known strength called standard solutions are 

 needed. Their strength is usually expressed in terms of normality. 

 A normal solution is one which contains in 1000 c.c. one gram of re- 

 placeable hydrogen or its equivalent. Thus to make 1000 c.c. of a 

 normal solution of hydrochloric acid (HC1), we would need 36.5 grams 

 of this acid containing one gram of replaceable hydrogen. This we 

 derive from the fact that the atomic weight of Cl is 35.5 and of H is i, 

 so that the molecular weight of HC1 is 36.5, and each 36.5 grams of this 

 acid contain i gram of replaceable hydrogen. 1 Sulphuric acid (H 2 SC>4) 

 has a molecular weight of 98 or (2+32+64), but 98 grams of sulphuric 

 acid contain 2 grams of replaceable hydrogen. Therefore, to prepare 

 a normal solution of this acid, we must use one half of 98 or 49 grams of 

 sulphuric (containing one gram of hydrogen) for 1000 c.c. of normal 

 solution. Oxalic acid (H 2 C 2 O 4 + 2H 2 O) has a molecular weight of 

 126 or (2 + 24 + 64 + 36). It also is a dibasic acid so we must use 

 only one-half of 126 or 63 grams of oxalic acid in making a liter of 

 normal solution. 



1 See table of atomic weights on last page preceding index. 



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