TLC Chromatography recap

Two important phases in chromatography are:

Why do you use different capillary tube for different sample?

• To save time during the experiment.
• To use the same tube for all samples.
• To reduce the cost of materials.
• To prevent cross-contamination and ensure accurate results.

How does each component in the sample is separated, during chromatography?

• All components are dissolved in a single solution.
• Based on their affinity with the mobile phase

• Size of the molecule

• Based on the state of the matters

Why the pencil line is needed?

• The pencil line is used for shading only.
• The pencil line is used as is used to mark the starting point

• The pencil line is a permanent mark on the paper.
• The pencil line is only for decorative purposes.

Why do you need another chemical added externally when the colour of the spots are not visible in TLC?

• It reacts with the compounds to make them visible.

• It sticks to the compounds and makes them show up under UV light or after staining.

• It dissolves the TLC plate so the spots can be seen.

• It changes the liquid used, making the compounds visible.

How would you calculate the Rf. value in chromatography?

• Rf = (distance traveled by solvent front) / (distance traveled by analyte)
• Rf = (total distance traveled by all components) / (distance traveled by solvent front)
• Rf = (distance from origin to analyte) / (distance from origin to baseline)
• Rf = (distance traveled by analyte) / (distance traveled by solvent front)

Identify the key features of the solvent system.

a

b

c

d

e

TLC plate

Solvent front

Chromatgraphy jar or tank

sample spots

Solvent