CHM 101/102
Chromatography I: Paper
General Chemistry 101/102
Laboratory Manual
University of North Carolina at Wilmington
Laboratory Manual
CHM 101/102
Chromatography I: Paper
•
Purpose
 Use the technique of paper chromatography to
separate a homogeneous mixture into its
individual components.
•
Safety Considerations
 Butanol and ammonia (both liquid and vapor) are
toxic and are strong skin and eye irritants. Keep
the ammonia in the hood and cover all butanol
and ammonia solutions.
 Dispose of butanol in the waste container in the
hood.
Laboratory Manual
CHM 101/102
Chromatography I: Paper
•
Procedure
 Place 25 mL of solvent in a 600 mL beaker. Cover
the beaker and set it aside.
 Obtain a piece of chromatography
paper and draw a line 1 cm from the
bottom with a pencil.
 Place a small spot of each indicator
on the line.
2 mm
1 cm
Laboratory Manual
25 mL
CHM 101/102
Chromatography I: Paper
•
Procedure
 Spot and label each of the four indicators and one
of the unknowns. The spots should be about 2 cm
apart.
 When the spots have dried, re-spot each one.
2 cm
Laboratory Manual
CHM 101/102
Chromatography I: Paper
•
Procedure
 When the spots have dried, form the
paper into a cylinder with the spots
facing out. Staple the edges
together being careful to keep them
straight and not allowing them to
touch.
 Place the cylinder into the 600
mL beaker and replace the
cover. Be sure the cylinder is
not touching the sides of the
beaker.
Laboratory Manual
CHM 101/102
Chromatography I: Paper
•
Procedure
 Let the chromatogram develop until the
solvent is 2 cm from the top of the paper.
 Remove the chromatogram from the
beaker and immediately mark the
solvent front with a pencil.
 Allow the chromatogram to dry before
going to the next step.
Laboratory Manual
CHM 101/102
Chromatography I: Paper
•
Procedure
 Take the chromatogram to the
hood and lightly mist it with water.
Place it in the ammonia chamber.
 Remove the cylinder
from the ammonia
chamber and unroll it.
Immediately circle the
colored regions with
a pencil.
Laboratory Manual
CHM 101/102
Chromatography I: Paper
•
Procedure
 Determine the RF values for
each colored spot in the
knowns and the unknown.
RF(a) =
a
d
 Use your computed RF
values to identify the
components of your
unknown.
Laboratory Manual
d
c
b
a