Chemistry 227 Thin Layer Chromatography

1
Chemistry 227Thin Layer Chromatography

• Determining the components in proprietary
  aspirins

2
Place 5 6 mLs of TLC solvent into a 100 150
mL beaker.

• Cover the beaker with a watch glass or a piece of
  Parafilm.

3
Heat a melting point capillary over a very small
flame.

• Rotate the capillary evenly with BOTH hands until
  the center softens and begins to sag.
• DONT PULL WHILE HEATING!!

4
Remove the capillary from the flame, NOW pull . .
.

• Hold it for a few seconds until the glass cools
  and re-sets.

5
Snap the capillary in two at the center.

• Now you have TWO spotters . . .

6
With a sharp pencil, draw a light origin line on
the TLC plate JUST ABOVE the solvent level in the
beaker

• Place four evenly spaced dots on the origin line,
  and identify the proposed spots at the top of the
  plate.

7
Place samples of the unknown and 3 references
into spotting plates

• Dip a spotter into a sample a bit of liquid is
  drawn into the capillary.

8
Touch the spotter to the plate a bit of sample
will wet the dot.

• Blow on the spot to hasten drying. Repeat with
  other spotters at their respective dots.

9
Place the plate into the developing beaker.

• It may take 10 15 minutes for the solvent front
  to approach the top. Mark the solvent front with
  a pencil, and allow the plate to air-dry.

10
When it is dry, examine the plate while it is in
the UV light box.
11
(No Transcript)
12
Compare the height to which the spots have risen
. . .

• Identify the components by comparing their
  positions with the references.

13
Sketch the results on your lab report.

• Identify the components you found.