The Grease Spot Test
Shows positive test for:
How to perform the test:
Two ml of methylene chloride is used to dissolve ~0.1 g of the sample to be tested. If solid material remains, grind it in a mortar and pestle and then filter to remove the solid from the test solution. If a liquid sample is insoluble, take the test solution from the methylene chloride layer. Several drops of the test solution are placed on a sheet of paper and the solvent allowed to evaporate.
A positive test is indicated by:
the formation of translucent spot on the paper.
a negative test (left) and a positive test (right)