Chlorophyll Chromatography
Project Overview: Did you know a green leaf is not actually just green? Hidden underneath all that chlorophyll are secret pigments just waiting to be uncovered. Learn how chromatography is used in real labs to separate mixtures.
Materials Required:
4 - 5 fresh green leaves (spinach is ideal)
Rubbing alcohol
A clear glass or jar
A coffee filter (cut into a strip) or strip of chromatography/filter paper
A coin or small spoon
Plastic wrap
Tape or a pencil (to suspend the strip)
Instructions:
Tear the leaves into small pieces and place them in the glass. Use the back of a coin or spoon to firmly crush and grind the leaves against the bottom of the glass.
Pour just enough rubbing alcohol into the glass to cover the crushed leaves. Cover the glass with plastic wrap and let it sit for 15 minutes, swirling occasionally, so the alcohol pulls the pigment out of the leaves.
Cut a strip of coffee filter paper or chromatography paper long enough to dip into the liquid without the top touching. Tape the top of the strip to a pencil so it can hang into the jar without touching the sides.
Lower the strip so only the very bottom edge touches the alcohol-pigment mixture. Rest the pencil across the top of the glass so the strip hangs straight down.
Wait 20 to 30 minutes and watch the liquid travel up the paper, separating into different color bands (green, yellow, and sometimes orange) as it goes. These are the different pigments hidden inside the leaf.
Congratulations, you just ran a real laboratory experiment using nothing but leaves and rubbing alcohol.
Fun Fact: That yellow-orange color hiding in your leaf has been there all along; it's just masked by chlorophyll. Once autumn hits and chlorophyll starts to break down, that hidden color finally gets its moment to shine. That is the real reason leaves change color in the fall.
