Paper Chromatography

Question 1

chromatography

Answer 1

Draw a pencil line on the chromatography paper about 2cm from
the bottom – this is the origin.
Spot the inks that you want to test on the origin line.
Place the chromatography paper into a glass jar
(make sure the level of the solvent is below the origin).
Wait for the solvent to travel up the paper and the dyes have separated.

Question 2

Tips

Answer 2

Always involves a mobile phase and a stationary phase.
How far the sample moves up the paper depends on how attracted it is to each phase.
If it has a greater affinity to the mobile phase it will travel further, if it has a greater affinity to the stationary phase it will stop sooner.

Question 3

Extra Info

Answer 3

The 2 different green inks have been separated into their component dyes.
They both contain blue but one contains yellow and one olive green.
You can measure the distance travelled from the initial ink spot to the dye (in this case blue) and also the overall distance the mobile phase travelled

Question 4

Rf

Answer 4

A chemical may be identified by its retention factor (Rf). This is a fixed value for a given chemical in a particular solvent.
Rf = Distance moved by chemical
Distance moved by solvent
Rf = 4/10 = 0.4