Chapter 23.8 - Chromatography

Question 1

Chromatography

Answer 1

Separation technique in which a mobile phase carrying a mixture moves in contact with a selectively adsorbant stationary phase

Question 2

Principal of chromatography

Answer 2

Principal on which all chromatography techniques are based is that the separation of a mixture of components occurs as a result of selective adsorbance on the components of the mixture on a stationary phase while carried by a mobile phase

Question 3

What are the different separation techniques in organic synthesis?

Answer 3

1. Chromatography
2. Infra-red spectrometry
3. Ultraviolet spectrometry

Question 4

What are the different types of chromatography?

Answer 4

Paper
TLC
Gas
Column
HPLC

Question 5

What are the mobile and stationary phases of paper chromatography?

Answer 5

mobile phase → solvent (water/alcohol)

stationary phase → paper

Question 6

What are the mobile and stationary phases of TLC?

Answer 6

mobile phase → solvent

stationary phase → thin layer of alumina or silica gel on a glass or metal plate

Question 7

What does TLC stand for?

Answer 7

Thin Layer Chromatography

Question 8

What are the mobile and stationary phases of column chromatography?

Answer 8

mobile phase → mixture of suitable solvents
stationary phase → solid adsorbent material like alumina or silica gel packed into a column (must be kept saturated to avoid cracking)

Question 9

Principal of gas chromatography

Answer 9

A gaseous mobile phase is in contact with a stationary phase (non-volatile liquid) and the separation of the mixture occurs as a result of selective adsorbance of the components of the mixture on the stationary phase

Question 10

What is the stationary phase of gas chromatography?

Answer 10

A non-volatile liquid (very high boiling point) spread across solid particles (silica/alumina) that are packed into a long coiled tube called the column

Question 11

What is gas chromatography used for?

Answer 11

To measure alcohol level in blood, urine samples, drug tests

Question 12

What does HPLC stand for?

Answer 12

High Performance Liquid Chromatography

Question 13

Principal of HPLC

Answer 13

A liquid mobile phase is in contact with a stationary phase(fine particles of a solid) and the separation of the mixture occurs as a result of selective adsorbance of the components of the mixture on the stationary phase

Question 14

What is HPLC used for?

Answer 14

To test for growth promoters in food

Question 15

Principal of Infra-red spectrometry

Answer 15

Organic compound adsorb infra-red radiation of certain frequencies. The combinations of frequencies that are adsorbed depend on the bonding within the molecule and are unique to the particular molecule. Different vibrating bonds adsorb IR at different frequencies

Question 16

What is infra-red spectrometry used for?

Answer 16

To identify illegal drugs, plastics, to back up breathalyser tests

Question 17

Principal of Ultraviolet Absorption Sprectrometry

Answer 17

Absorbance is directly proportional to the concentration of a substance

Question 18

What is Ultraviolet Absorption Sprectrometry used for?

Answer 18

In quantitative analysis to measure concentrations of certain organic compounds in a solution e.g. plant pigments and drugs

Question 19

Eluent

Answer 19

Solvent in chromatography

Question 20

Leution

Answer 20

Movement of pigments down through the stationary phase in column chromatography