374 



RADIOISOTOPES IN BIOLOGY AND AGRICULTURE 



review of this method has been compiled by Strain and SiilUvan (29). 

 Sato et al. (30) have presented a detailed discussion of an apparatus used 

 in the separation of calcium and phosphate ions, and also of the various 

 factors that influence the separation. Of particular interest is the ecjuip- 

 ment now commercially available that operates on the continuous-flow 

 principle. Some advantages are as follows: (a) relatively large amounts 

 of materials can be separated, (b) difficulties due to absorption by the 

 filter paper are minimized, (c) the choice of solvent or background elec- 

 trolyte is not as critical as in conventional paper electrophoresis, and (d) 



Td- 



8 

 cm 



m^ 



B 



12 

 cm 



i9-~j jjr'W*" 



Fig. 8-6. Paper-electrophoresis apparatus. .1 is a cover'?d glass cylinder, and B 

 indicates containers for buffer solution into which carbon or nichrome electrodes are 

 placed. The paper strip is supported on two glass rods. [From D. B. Zilversmit and 

 S. L. Hood, The Use of Blood Serum as Buffer for Paper-electrophoretic Studies of 

 Radioactive Yttrium, Proc. Soc. Exptl. Biol. Med., 84: 573-576 (1953).] 



no cutting up or elution of paper is required, since the fractions are col- 

 lected off drip points. 



Considerable apphcation has been made of the technique in which 

 paper electrophoresis is utilized without chromatographic separation. 

 Equipment is now commercially available. Durrum (31) has described 

 a method suitable for the separation of amino acids, peptides, or proteins 

 and has discussed many of the factors involved. Jermyn and Thomas 

 (32) have presented considerations in regard to the problem of liquid 

 flow in paper electrophoresis. Gordon et al. (33) described a simplified 

 paper electrophoresis apparatus that was used to identify the protein 

 associated with thyroxine. Zilversmit and Hood (34) reported the use of 

 this procedure to study the state of injected yttrium 91 in blood. The 

 apparatus employed was similar to that of Gordon et al. and is illustrated 

 in Fig. 8-6. Evaporation of water from the strips was minimized, 

 although not prevented, by covering the walls of the outer container with 

 moist filter paper. The filter-paper strips were moistened with the buffer 



