Chromatography

Question 1

Stationary Phase in TLC

Answer 1

Solid

Question 2

Mobile Phase in TLC

Answer 2

Liquid

Question 3

Separation Method in TLC

Answer 3

Adsorption onto solid

Question 4

Data Collection in TLC

Answer 4

Rf values

Question 5

Stationary Phase in GC

Answer 5

Solid or Liquid on a solid support

Question 6

Mobile Phase in GC

Answer 6

Gas

Question 7

Separation Method in GC

Answer 7

Relative solubility into liquid

Adsorption onto solid

Question 8

Data Collection in GC

Answer 8

Retention Time

Question 9

Rf value

Answer 9

Distance moved by component/distance moved by solvent

Question 10

Chromatography disadvantages

Answer 10

• Similar compounds often have similar Rf values of retention times
• Unknown compounds have no reference Rf values/retention times for comparison
• Difficult to find solvent that separates all components in a mixture

Question 11

Gas Chromatography - Mass Spectrometry

Answer 11

• GC can separate components by relative solubility or adsorption but cannot identify conclusively
• MS provides identification/detailed structural information by comparison of fragmentation but cannot separate
• Combining both techniques allows us to obtain a more powerful technique

Question 12

Uses of GC-MS

Answer 12

• Forensics
• Environmental analysis
• Airport security
• Space probes

Question 13

CHROMATOGRPAHY

Answer 13

An analytical technique that separates components in a mixture between a mobile phase and a stationary phase.

Question 14

MOBILE PHASE

Answer 14

The phase which moves – may be a liquid (LC) or a gas (GC).

Question 15

STATIONARY PHASE

Answer 15

The phase that does not move and may be a solid (TLC) or a liquid on a solid support (GC).

Question 16

RETENTION TIME

Answer 16

The time taken for a component to pass from the column inlet to the detector.