Sunday, 4 March 2012

Paper Chromatography Experiment

In chemistry, chromatography is a process for separating different components from a mixture.
 
 
Chromatography is achieved by passing a sample mixture - the scientific word for this being analyte - in a stream of solvent through some form of material that will provide resistance when chemical interactions are made.  I read some where that this is an interreaction not a reaction. Anyway, this happens between the components of the sample and the material.
 

You will need:
  • Paper kitchen roll or Coffee filter paper
  • Water
  • A glass
  • A pipette
  • Felt tips of different colours

STEP ONE

Get a strip of kitchen roll or a strip of coffee filter.

STEP TWO

At one end put a blob of colour using a felt tip about 1cm away from the end. 

STEP THREE

Fill a glass with water about 2 cm high.

STEP FOUR

Let a bit of the strip of kitchen roll touch the water so it gradually creeps up the paper.
 
Watch!  You may need to leave it for a good 10 minutes

WHAT IS HAPPENING?
 
As the water rises through the paper it then meets with the ink.  It will then start to travel up the paper with the water.  Different compounds in the ink travel different distances according to how strongly they interact with the paper. If done properly paper chromatography takes some time and the experiment is usually left to complete for some hours.  If you use felt tip pens I find that the results happen quite quickly.  My favourite colour to try is black but try different colours and see how they vary.
 
Experiment two
 
 
STEP ONE
 
Take a piece of kitchen paper this time so you have a square
 
of it rather than a strip or, alternatively, a coffee filter paper.
 
 
STEP TWO
 
Dot the paper with felt tip pens, leaving plenty of room
 
between each dot.
 
 
STEP THREE
 
Using a pipette, drop small amounts of water a drop at a time
 
and watch the colours separate.
 
 

These are a few photos from our last experiment with
 
chromatography!
 

2 comments:

  1. Thanks for this - we've had a go this morning!

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    Replies
    1. Cool! We had lots of fun with it yesterday! :)

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