RP12 - separation of species via thin layer chromatography

Question 1

Define stationary phase

Answer 1

A solid or liquid in chromatography held by a solid support

Question 2

Define mobile phase

Answer 2

A liquid or gas that moves through the stationary phase

Question 3

What is the stationary phase made up of?

Answer 3

Aluminium oxide or silicon oxide

Question 4

What is the use of thin layer chromatography?

Answer 4

Separate a mixture into its constituent parts for analysis

Question 5

Describe the process of TLC

Answer 5

Add solvent to a jar and seal
Draw pencil line 1cm from bottom of TLC plate
Spot samples along pencil line using capillary tube
Add TLC plate to jar, ensuring solvent is below pencil line
Solvent rises up plate, bringing sample components up
Draw line where solvent finishes
Allow plate to dry
If spots are colourless, use UV

Question 6

Why cant ink be used on TLC plate

Answer 6

Will dissolve in solvent and contaminate TLC

Question 7

What determines the Rf value of a spot

Answer 7

Solubility in mobile phase and retention by stationary phase

Question 8

Why do different amino acids have different Rf values?

Answer 8

They have different polarities that affect the retention in the stationary phase or solubility in the mobile phase