Chromatography
What is paper chromatography and what is it used for?
Chromatography is a method for separating the parts of a mixture of a solution containing different
chemicals. The different bonding properties of each molecule type are exploited.
It is used in the industry by:
Being used in scientific studies to identify unknown organic and inorganic compounds from a
mixture
It is used in the sequencing of DNA and RNA finger printing.
Used in testing of antibiotics and determining the pollutants in water
Used in the separation of proteins into homogenous groups for use in medicine
(starstruck,2019)
Apparatus for paper chromatography:
Leaves
Pestle and mortar
Chromatography paper
Pipette
Sand
Propanone solution
Capillary tube
Crocodile clip and magnet
Pencil
Beaker
lid
Method for paper chromatography:
1. Finely cut up some leaves and fill a mortar to about 2 cm depth.
2. Add a pinch of sand and about six drops of propanone from the teat pipette. Continue to
add sand and propanone until you end up with a concentrated liquid of the leaf that will
allow you to use a capillary tube to extract the liquid.
3. On a strip of chromatography paper, draw a pencil line 1.5 cm from the bottom.
4. Use the capillary tube to put liquid from the leaf extract onto the centre of the line. Keep the
spot as small as possible.
5. Allow the spot to dry, then add another spot on top. Add five more drops of solution, letting
each one dry before putting on the next. The idea is to build up a very concentrated small
spot on the paper.
6. Attach the paper to the lid.
7. Place no more than about 10 cm3 of propanone in the beaker and hang the paper so it dips
in the propanone. Ensure the propanone level is below the spot.