628 PANTOTHENIC ACID 



VI. Estimation 



A. CHEMICAL AND PHYSICAL METHODS 

 GEORGE M. BRIGGS and FLOYD S. DAFT 



Several chemical methods for estimation of pantothenic acid are avail- 

 able, although they seem especially suited only for relatively pure mixtures. 

 Two proposed methods are based on the liberation of /S-alanine by chemical 

 means and its subsequent determination by colorimetric tests. ^' ^" Recently 

 this has been extended to the determination of pantothenic acid in crude 

 materials (urine and wheat), and the values agree well with the results ob- 

 tained by biological assay. ^^' ^'^ Further studies are necessary, however, be- 

 fore chemical methods can be routinely used for biological materials. 



The estimation of pantothenic acid in pure vitamin mixtures is possible 

 by the cheijiical release and determination of pantoyl lactone or of pantoic 

 acid.^''' ^^ This method does not differentiate pantothenic acid from its in- 

 active lactone moiety, however. 



Also, it is known that pantothenic acid is reduced at the dropping mer- 

 cury electrode^ and may be measured by polarimetric analysis.^ These 

 methods are not specific enough, however, to be used to assay pantothenic 

 acid in natural materials. 



B. BIOLOGICAL METHODS 

 GEORGE M. BRIGGS and FLOYD S. DAFT 



Biological methods of assay are the only satisfactory methods thus far 

 suggested. Microbiological assays (discussed elsewhere) and animal assays 

 are both used with success. Microbiological methods are more rapid and 

 are the method of choice for routine purposes, whereas animal assays are 

 helpful chiefly for checking the accuracy of microbiological methods in the 

 determination of total pantothenic acid activity. 



In general, an animal assay of crude material measures not only panto- 

 thenic acid but also any "sparing" factor which might be present.* This 

 gives a greater significance to animal assays than to microbiological assays 

 as far as animal "pantothenic acid activity" of a material is concerned. 



1 R. Crokaert, Bull. soc. chim. biol. 31, 903 (1949). 



1" C. R. Szalkowski, W. J. Mader, and H. A. Frediani, Cereal Chem. 28, 218 (1951). 



1^ R. Crokaert, S. Moore, and E. J. Bigwood, Bull. soc. chim. biol. 33, 1209 (1951). 



!<= F. Y. Refai and B. S. Miller, Cereal Chem. 29, 469 (1952). 



1"^ E. G. Wollish and M. Schmall, Anal. Chem. 22, 10.3.3 (1950). 



1* C. R. Szalkowski and J. H. Davidson, Anal. Chem. 25, 1192 (1953). 



2 J. J. Lingane and O. L. Davis, /. Biol. Chem. 137, 567 (1941). 



3 D. V. Frost, Ind. Eng. Chem. Anal. Ed. 15, 306 (1943). 



4 F. S. Daft and K. Schwarz, Federation Proc. 11, 201 (1952). 



