EXPERIMENT: Paper Chromatography
ASSESSMENT CRITERIA: DCP, CE
Aim. To separate Ni, Mn, Co, and Zn ions present in a mixture by paper chromatography.
Apparatus: Glass jar with cover/ wide mouthed bottle / glass beaker (1000ml), capillary tube
with a fine tip, glass rod, 100ml beaker, Whatman filter paper No. 1.
Chemicals: Nickel nitrate, Manganese nitrate, Cobalt nitrate and Zinc nitrate, distilled water,
acetone, 20% HCl, 1% alizarin solution in ethanol and ammonia.
Procedure:
1. Cut a strip of Whatman filter paper about 1.5cm wide and length almost equal to that of
the jar.
2. Draw a line about 3cm from one end of the strip with a lead bonded pencil.
3. Prepare a solution of the metal nitrates of about 0.25N strength. Apply the spot of this
solution on the strip, almost in the middle of the pencil line, with the help of fine
capillary. Dry the spot. Repeat the process 2-3 times putting every drop on the same
spot.
4. Pour mobile phase, (a mixture of 88ml acetone + 12ml of 20% HCl), up to a depth of 2cm
in the jar.
5. Hang the paper strip in the jar with the help of a hook or glass rod in such a way that its
pencil line end just dips into the mobile phase.
6. Keep the jar undisturbed and allow to run the mobile phase at least 10-12 cms above
the pencil line.
7. Remove the paper strip and mark the solvent front with the pencil.
8. Dry the strip and then spray 1% alizarin solution in ethanol and ammonia over it.
If sprayer is not available, take 1% alizarin solution in ethanol and ammonia on a watch
glass and drag the strip over it in such a way that it touches the surface of the solution
and dry it.
9. Identify each ion from the colours and calculate their Rf values.
Record your observations, and discuss your results