27 



T ransference of the Pigments to Petroleum Ether 



As soon as the pigments were dissolved from the plant material 

 the solution was poured through a shallow pad of cotton supported in 

 a funnel, and the filtrate was collected in a 1-1„ separatory funnel. 

 The plant material was washed with a little of the solvent mixture, 

 and the pigments in the combined, filtered extracts were transferred 

 to the petroleum ether by the addition of about 500 to 600 mlo of 

 dilute (about 10 per cent) filtered, sodiiom chloride solutiono If -' 

 the pigments were not transferred completely to the petrolexim ether, 

 the separated aqueous methanol layer was re-extracted with more petro- 

 leum ether which was separated and added to the first extract. If 

 some of the pigments crystallized, it was necessary to add more petro- 

 leum ether or to start with a smaller quantity of the fresh plant ma= 

 terialo The deep green petroleum ether solution was washed twice with 

 a little dilute salt solution (or with water if emulsions did not form) 

 whereupon it was ready for chromatographic examination. It was not 

 necessary to dry the solution with anhydrous salts, and it was some- 

 times undesirable to do so owing to the sorption of the pigments. 



Some pigments are not stable in the petrolexim ether solutions. 

 It is inadvisable, therefore, to keep these solutions more than a few 

 minutes before separation of the pigments by chromatography. 



Chromatography of the Pigments 



The chromatographic columns of powdered sugar were prepared in 

 glass tubes about 3 cuic in diameter and 30 cm, long, tapered at the 

 base and loosely pl\igged with cotton„ Small portions of powdered 

 sugar, "Confectioners Powdered Sugar" containing 3 per cent starch 



