Abstract
When an ethylene dichloride solution of enniatin A is shaken with potassium picrate in potassium hydroxide solution, picrate anion is extracted into the organic phase in amount proportional to the enniatin concentration. Enniatin A can thus be determined spectrophotometrically in the range 5-60 μg/ml. Neutral lipids do not interfere. Valinomycin can be determined similarly, but cyclodepsipeptides that lack cationophoric properties are not estimated in this method.