Pigment Chromatography

Plant leaves contain different color pigments that give the leaf color. Plant pigments come in many different colors but we are the most familiar with chlorophyll because of its important job in photosynthesis. Chlorophyll is the green pigment that absorbs energy from the sun to power photosynthesis. As sunlight hits the leaves of the plant, yellow and green light are reflected while red and blue light are absorbed by chlorophyll. The reflected yellow and green light makes the leaves appear green to our eyes.

Fill in an answer based on the spinach leaf.

What question could you ask about the colors in this leaf? Does the spinach leaf have more than one color pigment?

Place your hypothesis in the box.

Predict what colors might show up.

Materials 1 piece of chromatography paper popsicle stick spinach juice 90% rubbing alcohol 1 metric ruler 1 beaker 1 pencil

Procedure 1. Write your name on one end of the chromatography paper.

2. Carefully measure 2cm from the other end and place a small, light mark.

3. Using the pipette or eye dropper, get a very small amount of the spinach juice. 4. Apply the juice in a line across the paper at the 2cm mark.

5. Allow 1 minute for the drop to soak into the paper. 6. Pour 20 mL of ethanol into the bottom of a beaker.

7. Place the bottom edge of the filter paper into the isopropyl alcohol but do not let the drops go under the alcohol line. 8. Observe the changes over 3 minutes.

9. Record and explain your observations. 10. Take the finished strip and tape it to your paper on page 3. Fill in these 2 boxes. Your observations are what you see on the paper strip. Interpret that data by explaining what you see.

Circle one of these based on whether your hypothesis was correct or incorrect.

Green chlorophyll yellow (carotene)

Complete the remainder of the lab. You may work with other students and use the internet to research the extension questions.