238 PIGMENTS 



silver sand in a mortar. Cover with 20 c.c. acetone and filter 

 over a pump ; wash the residue with more acetone and filter 

 again ; the filtrate will contain O'O2 gram chlorophyll. 



2. Dried powdered leaves do not part with their colour 

 on treatment with benzene or light petroleum, and only yield 

 chlorophyll very slowly to anhydrous alcohol, acetone, or 

 ether, but may be readily extracted by means of 90 per cent 

 alcohol or 80 per cent acetone yielding a green solution with 

 a strong red fluorescence. 



3. Prepare an ethereal solution of chlorophyll as follows : 

 About 15 c.c. of an 80 per cent acetone extract of dried leaves 

 are poured into 30 c.c. of ether contained in a tap funnel and 

 mixed with 50 c.c. water. The ethereal solution rises to the 

 surface. It should be washed four times with 50 c.c. of water 

 each time by carefully allowing the water to run down the 

 side of the funnel without shaking. If a 30 per cent methyl 

 alcoholic solution of potash is now run under the ether layer 

 a brown colour is produced at the junction of the two liquids. 

 The colour gradually changes to olive-green and finally back 

 to the original green. The reaction, which is known as the 

 " Phase Test," is due to the saponification of the chlorophyll 

 with formation of the potassium salt of chlorophyll in. Conse- 

 quently on dilution with water the green colour remains in 

 the aqueous layer and is no longer soluble in ether. 



4. Shake vigorously 5 c.c. of an ethereal solution of chloro- 

 phyll (prepared as above) with 2 c.c. of concentrated methyl 

 alcoholic potash. When the green colour has returned dilute 

 with 10 c.c. water, added in portions, and add a little more 

 ether. On shaking, two layers separate ; the lower aqueous 

 alkaline layer contains the chlorophyll while the ether contains 

 carotinoids. 



5. To separate xanthophyll from carotin wash the ethereal 

 solution of these two substances obtained from previous 

 experiment with a little water and evaporate to I c.c. Dilute 

 with 10 c.c. of light petroleum, and shake up two or three 

 times with 10 c.c. of 90 per cent methyl alcohol until the 

 latter is no longer coloured. The methyl alcohol will con- 

 tain the xanthophyll while the carotin will be in the light 

 petroleum. 



