THIN-LAYER CHROMATOGRAPHY STUDENT HANDOUT - PAGE 2

Using a pencil label the top of the TLC plate with 3 letters to indicate where each plant extract was added below.

 

 

 

 

 

 

Mark the bottom of the plate with 3 xs evenly spaced and about 2 cm above the bottom edge so the solvent can not wash away the spot of pigment when placed in the chromotography chamber. Be sure the xs are not on the edges of the TLC plate.

Figure 1
  1. Following the teacher's demonstration, carefully spot about 50 µL of your plant extract onto your marked TLC plate, using the capillary pipettes. This will require 30-50 droplets applied on the same spot. Remember that you want small, dark spots for best results.
  2. Obtain a different plant extract from another lab group and using a new capillary pipette, spot 50 µL about 1 cm from the first sample (Remember x marks the spot). Repeat with additional extracts. Allow to air dry.
  3. Carefully insert your TLC plate into the chromatography chamber. Solvent should not touch the spots. Cover the beaker with foil. See Figure 2.
  4. Remove the TLC plate when the solvent front reaches within one cm of the top of your plate (about 10 min). Circle pigment spots on the plastic side of the plate.