12 
Ingvar Jorgensen and Walter Stiles. 
Experiment 1. Extraction of the pigments. Required: small 
Buchner funnel with flask and a water pump; 20 c.c. 85% acetone 
or 90% alcohol. 
Two grams of leaf powder are sucked to a filter paper on the 
Buchner funnel and a small quantity of the solvent added. This is 
allowed to soak into the powder for a few minutes. The fluid is 
then sucked through with the pump. The operation is repeated until 
all the 20 c.c. of solvent has been added, when the powder is sucked 
dry. A deep blue green solution, with red fluorescence, is obtained 
which contains all the four pigments from the leaf. Usually the 
powder will still be coloured green as the extraction is not generally 
complete. 
Experiment 2. Transfer of the pigments front an acetone solution 
to an ether, or to a petrol ether, solution. Required : 1 separating 
funnel ; about 10 c.c. ether and 10 c.c. petrol ether; 5 c.c. acetone 
extraGt of leaves. 
Five c.c. of the acetone extract obtained in Experiment 1 are 
poured into double the quantity of ether contained in a separating 
funnel. An equal quantity of distilled water is added, this being 
poured gently down the side of the funnel in order to avoid the 
formation of emulsions. In the course of a few minutes, the ether 
layer separates out and now contains the pigments. The lower 
layer, which is slightly green, is run off. The addition of distilled 
water and subsequent removal of the lower layer is repeated about 
four times, in order completely to remove the acetone from the 
ether solution. If the ether solution should have become at all 
emulsified, it can be cleared by shaking with anhydrous sodium 
sulphate and filtering. 
A petrol ether solution may be obtained in the same way by 
using 10 c.c. of petrol ether in place of ether. 
Experiment 3. Demonstration of the two green pigments. 
Required : 10 c.c. petrol ether solution of mixed pigments ; 10 c.c. 
92% methyl alcohol; 2 separating funnels. 
The petrol ether solution from the last experiment is shaken 
with 10 c.c. 92% methyl alcohol. Two layers are formed of which 
the petrol ether layer contains chlorophyll a and the methyl alcohol 
layer chlorophyll b. The solution of chlorophyll a is blue green 
while that of chlorophyll b is a purer green, but the colour differ¬ 
ence between them is diminished owing to the presence of the 
yellow pigments, of which carotin is in the petrol ether, and 
xanthophyll in the methyl alcohol. 
