- 26 - 



to prevent caking, were tightly pressed (not tamped) into these tubes 

 with a plunger but slightly smaller than the diameter of the glass 

 tube^'^. These small portions, each about 2 cm, deep, were packed in 

 succession lintil the sugar column was about 25 om. deep. During this 

 packing, the glass tube was supported on a cork ring or stopper on a 

 wooden box. 



It was not necessary to dry the sugar or to screen it before 

 packing it into the chromatographic tubes. Sugar that had been ex- 

 posed to the moist atmosphere for several summer months at Hawaii and 

 at Chicago proved just as effective as that from freshly opened packages 

 or that dried in desiccators. Powdered sugar dried in an oven at 100* 

 did not form as uniform columns as the unheated preparations unless it 

 was carefully screened. 



For the chromatographic separations, a sugar column was attached 

 to a suction flask and a little of the deep green, petroleum ether 

 solution of the pigments was drawn into the upper layers until it formed 

 a green zone about 0.7 to 1,5 cm. deep. This zone was then washed with 

 petroleum ether containing about 0,5 P®^ cent n-propanol. Under these 

 conditions, the pigments separated rapidly from each other providing 

 a succession of green and yellow zones analogous to those indicated 

 already in Fig\ire 1,1. 



As the petroleum ether plus propanol wash liquid penetrated the 

 powdered sugar, there was little change in the color of the zones of 

 most of the sorbed pigments. But with violaxanthin and, particularly, 

 with a minor xanthophyll of certain green algae that is adsorbed just 

 above the violaxanthin, the initially yellow zones turned orange as 

 the petroleum ether plus propanol moved through them. At this stage. 



