IB Biology HL Lab Report

Separation of Photosynthetic pigments using Plant

Chromatography

Shantal Al Habib 17 May 2016

Aim:

The aim of this experiment is to separate and identify the pigments found in

different types of plants. Through this experiment, the variation between the

pigment levels in 4 different plants will also be observed.

Introduction:

Plants absorb light in order to carry out photosynthesis. This light is absorbed

by chloroplasts in plant cells. Through photosynthesis, plants synthesize their

own food.

Paper chromatography is normally used to separate mixtures of different

molecules since capillary action happens and allows the molecules of each

pigment to attract to one another and to the paper and thus, move up the

paper (“Lab Report On Plant Pigments and Photosynthesis Biology Essay”).

The pigments include Chlorophyll a, Chlorophyll b, Xanthophyll, and Carotene.

The Relative Mobility Factor (Rf) value is the distance that the solute traveled divided by the distance the solvent traveled (“Chromatography of Different Colored Leaves: Lab Report”). The distance traveled by the solvent is the line to which the original solution reached when the filter paper was dipped in the solution. The Rf values can be compared between different plant species to compare the pigments found in them.

Research Question:

How do the pigments separate in leaves compared to flowers?

Materials:

1. 1.0 g Leaves of Prunus avium

2. 1.0 g Jasminum sambac

3. 1.0 g Thlaspi arvense

4. 1.0 g Sinapis arvensis

5. 40.0 ml isopropyl alcohol

6. 1x syringe

7. 4x 50 ml beakers

8. 200.0 ml hot water

9. 4x bowls

10. 4x plastic cups

11. 1x knife

12. 4x strips of filter paper (2.0 cm x 20.0 cm)

13. 4x circles of filter paper

14. 1x electronic balance

15. 1x smasher

16. 1x ruler (0.05)

17. 1x black soft pencil

Processing

1. using your knife, cut the plants into small pieces

2. measure 1.0 gram of each of the plant types and put them in the

beakers

3. using the syringe, measure 10.0 ml of isopropyl alcohol and put it on top

of each of the plastic cups containing the plants

4. pour 50 ml of hot water in each of the 4 bowls

5. put the plastic cups in the bowls and cover the lids with your hands

6. Wait for 5 minutes or until the solution takes some color

7. Using the circular filter paper, filter out the solutions in the cups into 4

beakers

8. Using your ruler, measure 2 cm from the end and draw a line and draw a

ball in the middle of the line. The distance from the bottom of the paper

to this line is the distance traveled by the solution

9. Put the filter paper into the beakers and position it in a way that the

solution reaches the line drawn

10. Keep the solution in this way for 1 or 2 hours

11. After 2 hours, remove the filter paper

12. Identify the pigments on each paper according to the color and mark

the highest point of that color. The distance from the bottom of the

paper to this point is the distance traveled by the solvent

13. Using the ruler, measure the Rf value using the following equation:

𝑅𝑓 =𝐷𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑡𝑟𝑎𝑣𝑒𝑙𝑒𝑑 𝑏𝑦 𝑠𝑜𝑙𝑣𝑒𝑛𝑡

𝐷𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑡𝑟𝑎𝑣𝑒𝑙𝑒𝑑 𝑏𝑦 𝑡ℎ𝑒 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛

Data Collection:

Conclusion:

The separation of pigments varied between the types. Those that had a more

vibrant petal colors showed the separation evidently. Thlaspi arvense which

has very pale petals, did not separate the pigments evidently. The leaves had

the most pigmentation out of all the flowers. The pigments were clear and

opaque. It contained the darkest pigments (see fig. 7). The leaves have more

chloroplasts since they are the major photosynthetic structure. They have a

larger surface area and can absorb more light. Because of this, leaves have

more pigmentation since the pigments come from chloroplasts.

Evaluation and Improvement

A wider range of flowers can be used to identify the differences between

the pigments in leaves and in petals.

1 2 3 4 5

carotene 0.72 0.93 0.94 0.97 0.89

Xanthophyll 0.71 0.91 0.91 0.93 0.865

Chlorophyll A 0.78 0.86 0.87 0.837

Chlorophyll b 0.6 0.78 0.78 0.83 0.76

0.72

0.93 0.94

0.97

0.89

0.71

0.91 0.910.93

0.865

0.78

0.86 0.87

0.837

0.6

0.78 0.78

0.83

0.76

Rf

valu

e

Seperation of pigments in 4 plants by Chromatography

More colorful flowers can be used to see whether a certain color has

similar pigmentation to leaves

Leaves from shady and sunny areas could have been used to detect the

difference in pigments and therefore photosynthetic activity

Citations:

Vanuska, Elina. “Chromatography of Different Colored Leaves: Lab Report.”

elinavanuska.wordpress.com. Wordpress.com, n.d. Web. 14 May 2016.

“Lab Report On Plant Pigments And Photosynthesis Biology Essay.” Ukessays.com. All

Answers Ltd., 23 March 2015. Web. 14 May 2016.

Appendix:

Fig. 1: Jasminum sambac

Fig. 2: Sinapis arvensis

Fig. 3: Thlaspi arvense

Fig. 4: Prunus avium

Fig. 5: the samples from the 4 plants

Fig. 6: Filter paper dipped in the filtrated solution

Fig. 7: Filter paper with pigments