168 



CHEMICAL TECHNIQUES 



tillations, e.g., in arginase measurements. The ammonia was distilled 

 from vessel A into cap B, which was coated internally with paraffin 

 and charged with standard acid. Ramsay grease (thick) was used 

 to seal the parts together. Later it was found preferable to abandon 

 the use of this form of vessel for ammonia distillation (Briiel et al., 

 1946) (see page 283). 



Glass diffusion cells for the distillation of ammonia were described 

 first by Conway and Byrne (1933), and later by others (Figs. 41- 

 43) . Ammonia diffuses from the outer well into standard acid con- 



F 



67 mm.- 

 61 mm.- 

 40 mm.- 

 35 mm- 



^ "R^J 



^^- ~^ 



"' " 



Ie 



in 



Fig. 42, Gibbs and 

 Kirk (1934) diffusion 

 cell (cross section, one 

 half actual size). 



D 



\it ill UJ lU ll< OJ 



Fig. 41. Conway and Byrne (1933) 

 diffusion cell. Above, top view; 

 below, vertical, section on line AB. 



Fig. 43. Kinsey and Robinson 

 (1946) diffusion cells: upper, top 

 view; lower, side view. 



tained in the center well in the types shown in Figures 41 and 42 

 (available from Microchemical Specialties Co.). The Kinsey and 

 Robison (1946) apparatus (Fig. 43) consists of a Lucite plate 0.5 

 in. thick with rings 1 mm. deep having inner and outer diameters of 

 14 and 18 mm., respectively, reamed out of the plastic for one form 

 of cell (A); for the other form (B), rings of the same diameter but 

 8 mm. deep are reamed out and a center hole 4 mm. deep and 8 mm. 

 in diameter is drilled. In the A form cell, two glass vials are used 

 alone. Ammonia diffuses into the receiving solution placed in the 



