Aim
To separate the different pigments in inks or dyes using paper chromatography.
Equipment
-Inks (From Ballpoint pens)
-Marker Pens or Food Colouring
-250 ml Beaker
-Strip of Filter Paper
-Scissors
-Adhesive Tape
-Pencil or Ice-Block Stick
Method
-Cut a strip of filter paper that is long enough to reach the bottom of your beaker and able to wrap around your pencil or ice-block stick.
-Rule a line in pencil approximately 2 cm from the bottom of your piece of paper.
-Fill your beaker with enough chromatography solution to fill your beaker to a depth of 1 cm.
-Place a dot of ink above the ruled line on your filter paper. You need to produce a concentrated dot of ink so repeated applications may be necessary.
-Suspend the strip of Paper from the pencil or stick. You may need to use adhesive tape to stop it from falling into the solution.
-Wai to see what happens. It is important that you do not disturb the beaker. If the solution comes in contact with the ink dot, the ink will run down into the solution, rather than move up the filter paper.
Discussion
-The water ran up the filter paper causing the ink to run up as well.
Outline the origin of the term chromatography
Chromatography (Chroma - Greek for 'colour' and the word biography meaning 'words' or 'pictures')
Describe the type of mixtures that chromatography can separate
Inks and Dyes.
Explain why the pigments separate
The pigments separate because they have different solubilities in a solvent.
