Instrumentation

Question 1

Who invented chromatography

Answer 1

Russian botanist

Mikhail Tswett

Question 2

Uses of chromatography

Answer 2

• Separating different substances in a mixture

* Identifying and measuring the amount of the substances present

Question 3

Chromatography

Answer 3

A separation technique in which a mobile phase carrying a mixture moves in contact with a selectively absorbent stationary phase

Question 4

Principle of chromatography separation

Answer 4

Separation of a mixture of components occurs as a result of selective adsorbance of the components of the mixture on a stationary phase while carried by a mobile phase

Question 5

Processes of Paper chromatography

Answer 5

• End of paper is placed in a suitable solvent
• Solvent soaks up through the paper
• Dissolved the sample being analyzed
• Solvent - mobile phase moves up through paper - stationary phase

Question 6

Result of paper chromatography

Answer 6

Original sample separate out into its various components at different intervals along the paper

Question 7

Gas chromatography

Answer 7

Uses a gas as the mobile phase and non-volatile liquid with a high boiling point as the stationary phase spread on solo a inert alumina that are packed into a long coiled tube

Question 8

Processes of gas chromatography

Answer 8

• Sample being analyzed is injected into the hot column (syringe)
• Sample is vaporized and carried through tube using Ni, He or Argon (carrier gas)
• Components of the mixture are adsorbed to different extents on the stationary phase
• Carries a detector that records a signal and plots a gas chromatogram

Question 9

Principle of Gas chromatography

Answer 9

A gaseous mobile phase is in contact with a stationary phase and separation of the mixture occurs as a result of selective absorbance of the components of the mixture on the stationary phase

Question 10

Uses of gas chromatography

Answer 10

• Measure the level of alcohol in the blood or urine sample

* Carry out drug tests on athletes

Question 11

GC-MS

Answer 11

Separated components from gas spectrometry passed into mass spectrometer

Question 12

Uses of GC-MS

Answer 12

• Compounds can be analysed separately and identified
• Forensics science laboratory
• Monitor the performance of a pharmaceutical in the body
• Analyse atmosphere and soil on other planets

Question 13

High-performance liquid chromatography

Answer 13

Substance being analyzed is added to a liquid solvent (Mobile phase) which is passed over very fine silica particles (stationary phase)

Question 14

Why is a pump used to force the liquid through the column for HPLC

Answer 14

Better separation occurs if the particles in the stationary phase are very small and pass through slowly

Question 15

Principle of high-performance Liquid chromatography

Answer 15

A liquid mobile phase is In contact with a stationary phase and separation of the mixture occurs as a results of selective adsorbance of the components of the mixture on the stationary phase

Question 16

Processes of HPLC

Answer 16

• Injection of sample
• Pumping sample along the column
• Separation in the column
• Detection of components in the mixture
• Display of results

Question 17

Features of HPLC

Answer 17

• Separation is more efficient as a pump is used
• The column isn’t as long
• Lower temperature

Question 18

Uses of HPLC

Answer 18

• Analyse mixture of non-volatile compounds
• Analysis of food (additives in food)
• Concentration of alcohol in blood

Question 19

Infra-red Spectrometry

Answer 19

• Wavelengths are longer than those of visible light
• Invisible
• Given off by hot objects
• Absorbed by the vibrations of bonds in organic compounds

Question 20

Principle of infra-red spectrometry

Answer 20

Organic compound absorb infra-red radiation of certain frequencies which are absorbed depending on the bonding within the molecule

Question 21

Processes of Infra-red Spectrometry

Answer 21

• Passed through the sample being analyzed
• Certain fixed frequencies is adsorbed
• Adsorption spectrum is obtained

Question 22

Uses of infra-red spectrometry

Answer 22

Identify compounds

Identify plastics and illegal drugs

Question 23

Principle of ultraviolet adsorption Spectrometry

Answer 23

Absorbance is directly proportional to the concentration of a substance

Question 24

Processes of ultraviolet spectrometry

Answer 24

• Substance being analyzed is placed between a source of UV light and a detector
• Measures the intensity of light reaching it
• UV absorption spectrum is obtained

Question 25

Uses of UV

Answer 25

Detect presence of transition metals and plant pigments

Question 26

Principle of mass spectrometry

Answer 26

Charged particles moving in a magnetic field are deflected to different extents according to their masses and are thus separated according to these masses

Question 27

Processes of mass spectrometry

Answer 27

``` Vaporization Ionisation Acceleration Separation in a magnetic field Detection ```

Question 28

Uses of mass spectrometry

Answer 28

Identify the presence of isotopes Measure the relative abundances of isotopes Measure relative atomic masses and relative molecular massesIdentify unknown compounds