Chromatography

Name three photosynthetic pigments that can be identitied by chromatography

Chlorophyll A

Chlorophyll B

Carotenoids

stationary phase in chromatography

A solid or liquid surface that remains fixed

Mobile phase in chromatography

A solvent that moves through the stationary phase, carrying the pigments with it

Rf value in chromatography

ratio that describes how far a pigment travels relative to the solvent front

Steps to perform chromatography

Extract pigments

Prepare the chromatography strip

Develop the chromatogram

Analyze the results

Why might carotene travel further than chlorophyll on a chromatogram

Carotene is likely more soluble in the solvent and has a lower affinity for the stationary phase compared to chlorophyll

Formula for Rf values

Distance moved by pigment/Distance moved by solvent

What does a higher Rf value indicate about a pigment’s properties?

A higher Rf value indicates that the pigment is more soluble in the solvent and has a lower affinity for the stationary phase.

Purpose of chromatography in separating photosynthetic pigments

To separate and identify pigments based on their differing solubility and affinity for a stationary phase

What is a common mistake to avoid when performing chromatography?

Allowing the pigment spot to be submerged in the solvent, which causes the pigments to dissolve into the solvent pool.

What are carotenoids and what colors do they appear on a chromatogram?

Carotenoids are yellow and orange pigments, appearing as yellow or orange bands.

What are the two common types of chromatography?

1. Thin-Layer Chromatography (TLC)
2. Paper Chromatography.

How can the ability to separate and identify pigments contribute to our understanding of plant evolution

It can provide insights into how plants adapt to different light environments and ecological niches.

What color does chlorophyll b appear as on a chromatogram?

Yellow-green

What color does chlorophyll a appear on a chromatogram>

Dark green

importance of using a pencil to mark the solvent fron on a chromatogram

Ink can dissolve in the solvent and interfere with the results.