How to Test an Organic Compound for Purity

Organic compounds are natural products that contain carbon and hydrogen. They include carbohydrates (sugar, plants), proteins (fats, waxes, steroids), lipids and nucleic acids. You will often find organic compounds in the form of mixtures, so you must assess their purity before using them. Too many impurities can lead to explosions or fires. Impurities in medical substances can injure or kill a patient.

One of the easiest ways to test an organic compound for purity is to find the melting point of a similar pure substance, then warm your sample and compare the melting points of both substances.

Things You'll Need

• Mortar and pestle
• Glass capillary tube
• Pan
• Platinum resistance thermometer or heat resistant thermometer

Show More

Instructions

• 1

  Obtain a table of organic compounds' melting points. Clean a glass capillary tube with a neutral detergent. Dry it. Use a mortar and pestle to reduce your sample to powder.

• 2

  Put the powder inside the capillary tube. Pack the powder homogeneously. Put a high-accuracy thermometer that sustains heat inside the pan.

• 3

  Put the tube in a pan full of warm water. Heat the water to a few degrees below the expected melting point.

• 4

  Look at your sample carefully and record the temperature on the thermometer when you see the sample melting.