Thin Layer Chromatography (TLC):

Materials:
Thin-layer chromatography plate and a pencil (not a biro or felt tip pen)
Four test tubes in a stand and labelling
Three capillary tubes for use as micropipettes
Chromatography chamber: either a screw top jar tall enough to take the TLC plate, a small beaker with a Petri dish for a lid, or a commercial tank.
Access to a fume cupboard and short wavelength UV lamp
Chemicals:
For this particular experiment, both crude and re-crystallised samples of aspirin are compared with a known sample of aspirin.
Ethanol and dichloromethane
A few iodine crystals (3-4 per experiment is sufficient)
Samples for testing
Ethyl ethanoate as chromatography solvent
Notes and suggestions:
Commercial Chromatography Chambers are 27cm x 26.5cm x 7cm deep- just like a fish tank with no grooves inside to support the plates are very expensive!

You can use beakers, with a Petri dish on top or jars with lids; tall enough to hold the TLC plates. Try Hellendahl staining troughs.

For the TLC plates buy MK-105554 Box/25, 20cm x 20cm which is basically silica gel painted onto aluminium sheets, from Perth Scientific. You can cut these to size with scissors to fit the staining chambers or what other vessel you use; be sure not to order the glass plates as you will have trouble cutting them to size without them crumbling. They seem to only come in the one size as noted above.

If your school cannot afford to buy these plates, you can make your own using 50g Kieselguhr (silica gel powder) mixed with 60mL water. Make a paste and paint it on glass microscope slides (one side only) and allow to dry before use.

Can also use glass/plastic jars with screw-top lids (depending on the solvents in the mobile phase) or even beakers covered with cling-wrap. Do not use ice cream containers; the containers themselves work fine (if the plates are small enough to lean against the sides) but alcohols crack the lids.

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