Part II: TLC Analysis of Standards

TLC results visualized with a UV lamp and iodine chamber.

T L C spots are made visible with a UV lamp and exposure to iodine in a chamber. Spots are circled then their distances are measured in order to calculate retention factor values.

Visualizing the TLC plate

Materials needed: iodine chamber

Visualize the plate under the UV lamp. Gently circle any spots you see with a pencil.
CAUTION: Work with iodine in the fume hood and keep the iodine chamber capped at all times except when adding or removing plates. Place the plate in the iodine chamber and make sure it is not touching any iodine crystals. Remove it after 3 minutes and circle any spots you can see.
Calculate the Rf values for each spot. (see formula below)*

*Ideally spots will travel straight up. However, poor technique or even inconsistencies in the TLC plate can lead to deviations, such as the ones present in the plate shown in the video.

Retention factor equals the distance the compound moves from the spotting line over the distance the from the spotting line to the solvent front.

Equation to calculate R_f values.

Go back to performing the TLC analysis

Continue to view TLC Plates

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