Week 11: Gas Chromatography

Question 1

Define Gas Chromatography (GC) and explain its basic principle.

Question 2

What are the two phases involved in GC, and how do they interact?

Question 3

Explain the concept of retention time in GC.

Question 4

What factors influence the retention time of a compound in GC?

Question 5

Define selectivity factor (α) and explain its significance in GC.

Question 6

What is the resolution (Rs) in GC, and how is it calculated?

Question 7

Explain the concept of theoretical plates in GC.

Question 8

How does temperature affect the separation in GC?

Question 9

Describe the components of a typical GC instrument.

Question 10

What are the different types of injectors used in GC?

Question 11

Explain the function of the carrier gas in GC.

Question 12

What are the common types of carrier gases used in GC?

Question 13

Describe the different types of GC columns (packed vs. capillary).

Question 14

What are the advantages and disadvantages of packed and capillary columns?

Question 15

Explain the function of the detector in GC.

Question 16

Describe the following detectors and their applications: FID, TCD, ECD, MS.

Question 17

List at least five major applications of GC in various fields.

Question 18

How is GC used in environmental analysis?

Question 19

How is GC used in the pharmaceutical industry?

Question 20

How is GC used in food analysis?

Question 21

How is GC used in forensic science?

Question 22

What are some common problems encountered in GC analysis?

Question 23

How can you troubleshoot baseline noise in GC?

Question 24

How can you optimize the separation of two closely eluting peaks in GC?

Question 25

What are some common causes of peak tailing in GC?

Question 26

How can you minimize peak tailing in GC?

Question 27

Explain the concept of temperature programming in GC.

Question 28

What are the advantages of temperature programming?

Question 29

What is GC-MS, and how does it work?

Question 30

What are the advantages of using GC-MS for analysis?

Question 31

What is the mobile phase in gas chromatography?
a) A liquid solvent
b) A solid adsorbent
c) A carrier gas
d) A vacuum

Question 32

What is the stationary phase in gas chromatography?
a) A liquid solvent
b) A solid adsorbent
c) A carrier gas
d) A vacuum

Question 33

What is the retention time in gas chromatography?
a) The time it takes for the sample to be injected
b) The time it takes for the sample to pass through the column
c) The time it takes for the sample to reach the detector
d) The time it takes for the sample to be separated

Question 34

What is the retention factor in gas chromatography?
a) The ratio of the time the sample spends in the stationary phase to the time it spends in the mobile phase
b) The ratio of the time the sample spends in the mobile phase to the time it spends in the stationary phase
c) The ratio of the retention time to the dead time
d) The ratio of the dead time to the retention time

Question 35

What is the selectivity factor in gas chromatography?
a) The ratio of the retention factors of two components
b) The ratio of the retention times of two components
c) The ratio of the peak areas of two components
d) The ratio of the peak widths of two components

Question 36

What is the purpose of the injector in gas chromatography?
a) To introduce the sample into the column
b) To separate the components of the sample
c) To detect the components of the sample
d) To measure the retention times of the components of the sample

Question 37

What is the purpose of the column in gas chromatography?
a) To introduce the sample into the column
b) To separate the components of the sample
c) To detect the components of the sample
d) To measure the retention times of the components of the sample

Question 38

What is the purpose of the detector in gas chromatography?
a) To introduce the sample into the column
b) To separate the components of the sample
c) To detect the components of the sample
d) To measure the retention times of the components of the sample

Question 39

What is the most common type of detector used in gas chromatography?
a) Flame ionization detector (FID)
b) Thermal conductivity detector (TCD)
c) Electron capture detector (ECD)
d) Mass spectrometer (MS)

Question 40

What is the difference between a packed column and a capillary column in gas chromatography?
a) Packed columns are longer than capillary columns
b) Packed columns are wider than capillary columns
c) Packed columns are filled with a solid support material, while capillary columns are not
d) Packed columns are used for gas chromatography, while capillary columns are used for liquid chromatography

Question 41

What is gas chromatography used for?
a) To separate and analyze mixtures of volatile compounds
b) To separate and analyze mixtures of non-volatile compounds
c) To separate and analyze mixtures of ions
d) To separate and analyze mixtures of polymers

Question 42

What are some of the applications of gas chromatography?
a) Environmental analysis
b) Food analysis
c) pharmaceutical analysis
d) All of the above

Question 43

What is the advantage of using gas chromatography over other analytical techniques?
a) It is a very sensitive technique
b) It is a very specific technique
c) It is a very fast technique
d) All of the above

Question 44

What is the disadvantage of using gas chromatography?
a) It can only be used to analyze volatile compounds
b) It is a very expensive technique
c) It is a very complex technique
d) It is a very time-consuming technique

Question 45

How can the resolution of a gas chromatogram be improved?
a) By increasing the temperature of the column
b) By decreasing the flow rate of the carrier gas
c) By increasing the length of the column
d) All of the above