Each radioactive compound was disso

Each radioactive compound was dissolved
in n-heptane and extracted with alkaline ethanol (8).
The ethanol was acidified and fatty acids were reextracted
into fresh heptane. Heptane (50 ml) containing
the radioactive compound then was extracted
with an equal volume of 0.01 N H$04 in a separatory
funnel to insure removal of any remaining traces of
water-soluble radioactive impurities, and unlabeled carrier
fatty arid (10-20 peq/ml) was added