You can use paper chromatography to see the different pigments that produce the colors in leaves. Most plants contain several pigment molecules, so experiment with different leaves to see the wide range of pigments. This takes about 2 hours.
What You Need
- Leaves
- Small Jars with Lids
- Rubbing Alcohol (ethyl alcohol or methyl alcohol)
- Coffee Filters
- Hot Water
- Shallow Pan
- Kitchen Utensils
Instructions
- Take 2-3 large leaves (or the equivalent with smaller leaves), tear them into tiny pieces, and place them into small jars with lids.
- Add enough alcohol to just cover the leaves.
- Loosely cover the jars and set them into a shallow pan containing an inch or so of hot tap water.
- Let the jars sit in the hot water for at least a half hour. Replace the hot water as it cools and swirl the jars from time to time.
- The jars are ‘done’ when the alcohol has picked up color from the leaves. The darker the color, the brighter the chromatogram will be.
- Cut or tear a long strip of coffee filter paper for each jar.
- Place one strip of paper into each jar, with one end in the alcohol and the other outside of the jar.
- As the alcohol evaporates, it will pull the pigment up the paper, separating pigments according to size (largest will move the shortest distance).
- After 30-90 minutes (or until the desired separation is obtained), remove the strips of paper and allow them to dry.
- Can you identify which pigments are present? Does the season in which the leaves are picked affect their colors?
Tips for Success
- Try using frozen chopped spinach leaves.
- Experiment with other types of paper.
- You can substitute other alcohols for the rubbing alcohol, such as ethyl alcohol or methyl alcohol.
- If your chromatogram is pale, next time use more leaves and/or smaller pieces to yield more pigment.
