• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

My aim is to extract the various photosynthetic pigments from a grass tissue and later to separate them and determine which one is which by using thin layer chromatography.

Extracts from this document...


Klaudia Stadnicka Due 28.June.2002 Biology; IB5 LAB REPORT #7 CHROMOTEMOGRAPHIC SEPERATION OF PLANT PIGMENTS AIM: My aim is to extract the various photosynthetic pigments from a grass tissue and later to separate them and determine which one is which by using thin layer chromatography. To calculate Rf values for all of the pigments. Hypothesis: I expect to observe various pigments extracted. There will be a distinction between them and separation will occur due to the pigments' different solubility and attraction to the static phase. Prediction: I predict that separation of each of the pigments will occur and will be able to be observed. I also predict that the pigment that will travel the closest is chlorophyll b, and then chlorophyll a, followed by xantophyll and at the end there will be cartenoid pigments. Variables: There are no variables in this specific lab, because it is an observation lab, where we are meant to observe separation of pigments. METHOD: Equipment: * A few grass leaves * 2 glass microscope slides * blu tac * 1 glass micro pipette * 10 cm3 propanone (acetone) * 1 small watch glass * 1 electric hair drier * 1 very fine paintbrush * 2 - 3 TLC chromatography strips (1.25 cm x 6.7 cm) * 1 glass specimen tube, (2 cm x 7.5 cm) * 1 cork to fit the tube, with a horizontal V-slit * 7 cm3 chromatography running solvent per tube * 1 pencil * seeker (mounted needle) ...read more.


An Rf value is measured in order to represent the distance a pigment traveled in comparison to the solvent, which is also a representation of solubility of a specific pigment and their attraction to the static phase. Rf = distance run by pigments / distance run by solvent The Rf value from my experiment: Pigment Rf value Color Chlorophyll b 0.7 Dark green Chlorophyll a 0.5 Pale green Xantophyll 0.93 Yellow Though, the other group got some very nice results, where a separation could be seen very easily. We achieved what we expected a lucid distinction between the pigments, where they moved different distances depending on which pigment we were looking. The common, stated, official Rf values: Pigment Rf value Color Chlorophyll b 0.47 Dark blue-green Chlorophyll a 0.65 Green Xantophyll 0.71 Yellow-brown Phaeophytin 0.86 Yellow-green Carotene 0.96 Yellow DATA ANALYSIS: Chromatography has as its objective separation of molecules depending on their solubility (in this case it is the separation of various pigments). In paper chromatography, when you place a colored chemical sample on a filter paper, you can get the colors to separate from the sample by placing one end of the paper in a solvent. As the solvent diffuses up the paper, it dissolves the various molecules in the sample varying on the polarities of the molecules and the solvent. If the sample contains more than one color - it has more than one kind of molecule. The differences in the chemical structures of each kind of molecule, determine also their polarity, which will also alter while the structure alters. ...read more.


I suppose it might be due to the solvent's polarity. Let's talk about the second results, though, where our hypothesis is supported, because we see the same pattern as expected and the separation of pigments occurred. The Rf values are alike the ones received by the specialists. The pigments move the further, the more soluble they are, the lighter they are and the less attracted to the paper they are. There of course were some weaknesses and a few modifications might have been done. Weaknesses: Our main weakness is that we didn't make any replicates, which would make our results more accurate and reliable. We should have done a few more paper tests using exactly the same method. I feel as another weakness was that we didn't include any variables; we didn't even check how pigments of another plant would react. Modifications: The most important modification is to do replicates of the same experiment and at the end look on the average results. We could have also experimented with different stationary and mobile phases e.g. aluminum foil and spray aluminum oxide. We could have also looked on the experiment when using various solvents, which would highly affect the results. We could have also left the paper for a longer/shorter time to observe the differences. We should have ensured ourselves that the pigments were above the solvent, what is crucial, otherwise the pigments would be solved in the solvent. Maybe that is what happened in our first experiment. We could have also tested different plants and check the differences - compare the results. Sources: Some internet sites: http://www.grossmont.net/cmilgrim/Bio120/Lab/Paper_Chromotography_Results.htm http://www.mrs.umn.edu/~goochv/CellBio/labs/photosynthesislab/photo.html http://www-saps.plantsci.cam.ac.uk/worksheets/project3.htm http://www.nasaexplores.com/lessons/01-037/9-12_2.html Biology book: "Advanced Biology for You" by Gareth Williams Class notes Own knowledge ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Green Plants as Organisms section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Green Plants as Organisms essays

  1. Tank Chromatography.

    another spot of the same colour was placed on top and was allowed to dry once more. This was repeated several times to build up the concentration of the ink at the specific point and saturate the paper, which would inevitably improve the visibility of the results.

  2. Separation of photosynthetic pigments by paper chromatography.

    paper from the boiling tube and use the small glass tube provided, place a drop of the pigment solution at the centre of the pencil line. Dry the spot under the heat from a hairdryer or let it dry naturally.

  1. Transpiration of A Pine Needle Lab

    a plant in constant darkness and a plant kept in humid conditions would transpire less than the control group. Materials and Methods This experiment occurred on the lab benches in the biology classroom of Mr. Resch. We first got plastic Ziploc bags which we filled halfway with water from the sink.

  2. Germination lab _ siddharth nair

    * Make sure that all the seed samples are placed in the same conditions so that they receive the same amount of light in a week. * The tissues used should all be of the same size, material and thickness.

  1. Photosynthesis - revision notes

    What next???? Q. What happens to the glucose the leaf makes? A. It is either stored as starch or converted to another type of sugar: sucrose. * Some is converted into starch and stored. * Some is broken down straight away in to sucrose to provide energy for leaf to produce more chlorophyll.

  2. Three separate experiments which are to be carried out to investigate a plant's unique ...

    * I predict that there will be the same number of stomata per square millimetre on each leaf. This is because the leaves are on the same plant, and so the genetics of the plant will determine how many stomata there are in a certain area.

  1. Absorption Spectrum of Chlorophyll.

    The short-lived fluorescent state is produced by the excitation of either the blue or red absorption band. Electrons return to their ground states by emission of fluorescence, dissipation of heat or by a chemical reaction. A possibility of transferring the energy from one pigment molecule to another also exists.

  2. Investigation using thin layer of chromatography to separate photosynthesis pigment

    The mixture also affects chromatograph movement as mixtures of solvents can also have different effects depending on the amount of each solvent. As the polarity of a substance is increase all the components of the mixture will move faster during the chromatography experiment To make the chromatography technique more scientific, Rf value was introduced (Retention Value).

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work