660 



VI. CAROTENOIDS AND RELATED COMPOUNDS 



Strain^^° has recently shown that the Winterstein arrangement is not an 

 absohite one, since the order of adsorption depends upon the adsorbent and 

 the solvent. ^2*'*^ ''^^^ Powdered sugar attracts the polar hydroxyl groups 



Table 35 

 Order of Adsorption of Carotenoids on Tswett Column" 



" Adapted from A. Winterstein.^^^p. 1414, by L. Zechmeister, Die Carotinoide, Springer, 

 Berlin, 1934, p. 95. 



* Arranged in decreasing order of affinity. The substance with a lower number will 

 appear higher on the column than any substance having a higher number. 



" Values in parentheses give equivalent conjugated bonds, assuming each double bond 

 conjugated with a ketone has a value of 1.5 times that of the carbon double bond. 



"^ Zechmeister^'^ gives this position as below cryptoxanthin, but the relation to physa- 

 lien is not established. 



* Hydroxyl groups combined in ester linkage. 



of the xanthophylls by preference, while it has little affinity for the unsatu- 

 rated portions of the carotenoids. On the other hand, magnesia primarily 

 attracts the unsaturated linkages of both the carotenes and the xantho- 

 phylls. 



"0 H. H. Strain, ./. Am. Chem. Soc, 70, 588-591 (1948). 



"1 H. H. Strain, W. M. Manning, and G. Hardin, Biol. Bull, 86, 169-191 (1944). 



"2 H. H. Strain, Ind. Eng. Chem., Anal. Ed., 18, 605-609 (1946). 



