TLC

Question 1

TLC

Answer 1

Thin-Layer Chromatography (TLC) is a quick and simple technique used to separate and identify small components in a mixture — based on their polarity and solubility.

Question 2

Stationary phase

Answer 2

silica gel or alumina (very polar) on the thin glass plate

Question 3

Mobile phase

Answer 3

The mobile phase in TLC is a liquid solvent or mixture of solvents, it moves up the TLC plate by capilliry action and carries the sample with it.

non-polar - hexane, toluene

polar - ethanol, methanol, water, acetone

mixtures - hexane + ethyl acetate

Question 4

Separation

Answer 4

1. prepare TLC plate
2. Draw a baseline
3. spot the sample
4. prepare the solvent system (mobile phase)
5. place the TLC plate in the chamber
6. let the solvent rise
7. remove and mark the solvent front
8. visualise the spots
9. measure the Rf (optimal)

separation is based on how well components dissolve in the mobile phase and how well they stick to the stationary phase

Question 5

Types of mixtures separated

Answer 5

• drugs and medicine
• plant extracts
• amino acids
• food dyes
• ink

Question 6

Advantages

Answer 6

• fast and simple
• better separation that paper chromatography
• uses small sample volumes
• flexible solvent choice

Question 7

Disadvantanges

Answer 7

• not highly quantitative
• sample may degrade (air, pollutants, light)
• limited to small, soluble compounds
• human errors can affect results.