mixture - chromatography · chromatography is a laboratory technique used for the separation of...

Mixture - ChromatographyColour separation through paper chromatography.

Written By: Manikandan S

Mixture - Chromatography 2020-05-07[major]1.1Release:Guide ID: 714 -

This document was generated on 2020-05-07 11:56:04 PM (MST).

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INTRODUCTION

Chromatography is a laboratory technique used for the separation of mixtures. The mixture isdissolved in a fluid called the mobile phase, which carries it through a structure holding anothermaterial called the stationary phase. The various constituents of the mixture travel at differentspeeds, causing them to separate.

TOOLS:Plastic Bottle (1)Scissors (1)Scale/Ruler (1)Pen/Pencil (1)

PARTS:Acetone (1)Bixa Seeds (1)Sample Container (1)Wooden Skewer (1)10 cm x 10 cm Tissue Paper (1)



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— Precautions

Scissors have functional sharp edges. Handle with care.

Be careful while using chemicals. Avoid touching them with bare hands and do not inhale/ingestthem.

Do not leave the acetone bottle open for a long time, as acetone is volatile.

— Step 1 - Extracting Pigment from Seeds

Take 10 -15 bixa seeds in a container. Add 20 drops of acetone to the container.

Close the lid of the container. Shake the container, till the colour of acetone turns orange.

Observe the colour released from the seeds after a few seconds of adding acetone.

As acetone is volatile, it will evaporate quickly in a few minutes.



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— Step 2 - Preparing the Filter Paper

Fold a filter paper, exactly, in half. The filter paper resembles a semicircle.

Fold the semicircle shaped paper in half, again. Now, the paper resembles a cone.

Cut a small portion of the pointed end of the cone, using scissors.

Unfold the filter paper and observe the hole at the centre of the circle.

— Step 3 - Transferring Pigment to Filter Paper

Mark a dot 5 mm away from the hole.

Similarly mark another dot opposite to the previous one.

Use the blunt end of a skewer to transfer the extracted pigment to the filter paper, on the pencil-dotmarked earlier.



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— Step 4 - Preparing a Wick

Prepare a wick using a tissue paper as shown in the picture.

Insert the wick into the prepared filter paper as shown in the picture.

Pour the given acetone into a plastic container.

Insert the filter paper set-up into the plastic container as shown.

Leave the set-up undisturbed for some time.

— Step 5 - Pigment Separation

The filter paper absorbs acetone through the tissue paper.

Observe the colour separation, at an interval of 5 minutes up to 15 minutes.

Leave the set-up undisturbed until the pigment separates into two colours.



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— Step 6 - Drying Filter Paper

Allow the filter paper to dry for a minute after detaching it from the set-up.

The pigments (in the acetone sample) may be identified as Xanthophylls and Carotenes.

— Troubleshooting

Pigments are not separated properly - Increase the concentration of the extract for betterseparation, i.e. use less solvent/more bixa seeds.

Separation not uniform - Make sure one end of the tissue paper is held by the hole.



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— Suggested Variations

Variation 1 - Replace with Sketch colours.

Variation 2 - Replace tissue wick with a cotton wick.

Variation 3 - By colour addition.

For more variations, Go to Mixture - Chromatography (Variations).



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