Plant Pigment Chromatography

Discussion in 'Supporting Biology' started by GeorgetheScienceTech, May 25, 2018.

  1. Its in the bin George but it is the best I have seen/done although not quite as good as yours. ;):)
     
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  2. Cheers Mate. I'm glad it's been good. But wait, what about my Pixie/Fairy Washing Up Team? I thought that they had deserted to you, as you. like me think it is not a Technical task. They wouldn't have gone to Dod @Dod as they have no knowledge of Doric.:D:D:D
     
    Last edited: Jun 15, 2018
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  3. If you need a washing up team George head down to the dinner hall, they are specialists. ;)
     
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  4. But what about all these Technicians who believe that Washing Up is a technical task Allan? I don't think that we are ever going to move forward as long as this is indoctrinated into mostTechnicians. I have no problem with an Assistant Technician or Glassware Washer carrying out this task.:);)
     
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  5. Then let those techs be subject to the same wages as the kitchen staff for the amount of time they spend washing up. They arent worth any more per hour than them. That might hurt but its the truth.
     
  6. Hello, sorry I am catching this thread a bit late, can you please tell me whether you used paper or TLC for your chromatograms George...thanks a bunch.
     
  7. paper chromatog of spinach pigments.JPG
    TLC Natasha. It always gives "cleaner, sharper" bands.:);)

    Here's Paper Chromatogram. Do you see the difference in quality?
     
  8. Yeah, definitely better on Thin Layer. Thanks.
     
  9. This is good. I note you have cut the top right hand corner of the plate. I read somewhere that this helps stop curved chromatograms so this probably proves it does? :)
     
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  10. Hi Sharon.:) Well spotted. The Chromatogram with the Heuchera where the top right Corner is cut is a reference point in the same way that SDS_PAGE gels are marked. If you look at the Paper Chromatography pic I posted you will see that the bottom of the chromatography paper has been cut into a "Wick". This ensures that the Mobile Phase moves uniformly up the paper.;)
     
  11. exemplar chromo3.png
    Just for you Allan - pigments from edible Cherry leaves.:D:DNotice that the Chlorophyll a appears slightly blue-green incontrast to Chlorophyll b which is olive-green.

    exemplar chromo2-1.png
     
    Last edited: Jul 4, 2018
  12. Hi George. This is my chromatogram done this morning using grass from the garden and following the SAPs method. The running solvent is Cyclohexane (5 parts); Propanone (3 parts); and Petroleum ether (40-60C) (2 parts). The Rf values I got don't quite match what's expected, so please could you help me identify the bands I've got? Thanks in advance :)

    20180706_093934.jpg
     
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  13. Nice Chromatogram Stokes1. The top yellow band is Beta-Carotene then moving down the Chromatogram we have Pheopyhtin (Chlorophyll a without the Magnesium cation) then Chlorophyll a then Chlorophyll b (just below Chlorophyll a). The broad yellow band just above and below the Chlorophyll b band is Lutein. The other yellow bands near to the origin are Violaxanthin and Neoxanthin (has the lowest Rf value). The Rf values look OK to me - they are all in the expected order. You won't get the same values as the SAPS experiment because you used Grass whilst SAPS used a Spider Plant. A good effort.:);)
     
  14. Why thank you, kind Sir!!!!

    Interesting that you say the SAPs method uses a spider plant though.......I picked grass precisely because that was what it said in the document I downloaded from this link:

    http://www.saps.org.uk/secondary/teaching-resources/1347-a-level-set-practials-tlc

    But thank you for helping with the ID of the bands I got. I will pass your reply on to the teacher who ran the practical, as she will find it helpful for when this practical comes round again next year! Much appreciated :)
     
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  15. Wonderful to meet Ally @Ally, DMS @DMS, Vee @Vee and others at The Conference at York last Thursday and Friday. You wonderful Techs all seemed surprised to meet me in person. Great Conference wasn't it? York
    It's always a pleasure Stokes1. I've just done a Chromatogram using a grass extract. I'll upload the pic when I get my USB cable sorted. It's true that in the past SAPS recommended Grass (especially young Grass). :);)
     
  16. Thanks George - I look forward to seeing how they compare. I have to admit it was quite a challenge to find some lush, green, healthy-looking grass in this heat wave! We're never satisfied, are we? We're always moaning that teachers want to do plant / photosynthesis practicals in the winter - who'd have thought that it would still be difficult in July?! :D:rolleyes:
     
  17. My motto is "Always be prepared!". I obtain my extracts and concentrate them. If kept in the dark they can be used up to 2 years.:D:D
     
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  18. grass extract-combined-2.png
    As promised Stokes 1. I hope that this is of help.

    View attachment 1644
     
    Last edited: Jul 11, 2018
  19. Fabulous George - thank you :)
     
  20. If you don't have a fume cupboard or have lots of students you might like this method from UncleBob at CLEAPSS http://science.cleapss.org.uk/Resource/Thin-layer-chromatography-of-plant-pigments.pdf
    Extracting the pigment this way avoids mess. The chromatogram is run in a universal tube or McCartney bottle to contain the solvents and uses very small volumes - making it safer.
    If you are struggling to find leaves, the bagged spinach from the supermarket works really well and is available pretty much all year round.
    Regarding the Rf values - I think the same pigment should give the same Rf value in the same solvent regardless of the species the pigment came from.
    BUT even if you used the same recipe as SAPS you might still have a slightly different solvent if one of the ingredients evaporated off for example. Hope that helps.