Gas Chromatography General Knowledge Quiz | Gas Chromatography General Knowledge Multiple Choice Questions(MCQs) & Answers

Questions
1 What are the benefits of decreasing the column internal diameter?
A Increased sample capacity
B Increased resolution
C Reduced risk of column overloading
D All of the above

Answer: Increased resolution
2 Helium is generally preferred as carrier gas over nitrogen and hydrogen because
A it is inert
B it has a lower viscosity
C it doubles up as a party gas for balloons and funny voices
D all of above

Answer: all of above

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3 What does the selectivity factor describe?
A The proportional difference in widths of two chromatographic peaks
B The maximum number of different species which a column can separate simultaneously
C The relative separation achieved between two species
D None of the above

Answer: The relative separation achieved between two species
4 Theoretical plates are used to
A estimate the efficiency of a column
B determine the thickness of the stationary phase
C measure the distribution of the analyte between mobile and stationary phases
D None of the above

Answer: estimate the efficiency of a column
5 Split injection is carried out by
A splitting the sample into smaller portions to inject sequentially
B splitting the sample into smaller portions to inject at the same time through parallel ports
C splitting off some of the sample so that it does not enter the column
D none of the above

Answer: splitting off some of the sample so that it does not enter the column
6 Headspace analysis is carried out in order to
A analyse volatile compounds from solid or liquid samples
B determine the psychological state of the tutor
C analyse the column contents ahead of the sample
D determine non-volatiles

Answer: analyse volatile compounds from solid or liquid samples
7 Which of the following detectors give mass flow-dependent signals?
A Electron capture detector
B Field ionisation detector
C Thermal conductivity detector
D All of the above

Answer: Field ionisation detector
8 retention gap is placed between the injector and the front of the column to
A retain contaminants and prevent them from reaching the column
B retain the sample and release it gradually to the column
C prevent backflush of the injected solution
D all of the above

Answer: retain contaminants and prevent them from reaching the column
9 In column switching chromatography
A compounds trapped on one column are eluted to another column
B one column is removed and replaced by another
C the flow to the column is switched on and off repeatedly
D any of the above

Answer: compounds trapped on one column are eluted to another column
10 Which of the statements is correct?
A Gas chromatography is used to analyse gases
B Gas chromatography is used to analyse solids
C Gas chromatography is used to analyse gases, solutions and solids
D All of the above

Answer: All of the above
11 Derivatisation of a sample is carried out to
A reduce polarity of the analytes
B increase the detector response
C increase volatility of the analytes
D all of the above

Answer: all of the above
12 Resolution is proportional to the
A number of theoretical plates in a column
B square root of the number of theoretical plates in a column
C square of the number of theoretical plates in a column
D cube root of the number of theoretical plates in a column

Answer: square root of the number of theoretical plates in a column
13 What is the typical internal diameter of fused silica capillary columns?
A 0.2-0.3 mm
B 0.3-0.5mm
C 0.5-1.0 mm
D 1.0-2.0 mm

Answer: 0.2-0.3 mm
14 What useful information can be found from a Van Deemter plot?
A The selectivity factor
B Optimum mobile phase flow rate
C Optimum column temperature
D Optimum column length

Answer: Optimum mobile phase flow rate
15 Which of the following detectors give concentration-dependent signals?
A Electron-capture detector
B Thermal conductivity
C Infra-red detector
D All of these

Answer: All of these
16 The GC trace obtained after an experiment is called a
A chromatograph
B chromatogram
C chromatophore
D graph

Answer: chromatogram
17 Which of these effects result from slow injection of a large sample volume?
A Increased resolution
B Decreased resolution
C Non-linear detector response
D Constant resolution

Answer: Decreased resolution
18 Which of the following is not used for detection in GC?
A Infrared spectroscopy
B NMR
C Flame ionisation
D Electrical conductivity

Answer: NMR
19 Sample retention in the column is measured by
A retention time
B retention factor
C retention index
D all of these

Answer: all of these
20 Column bleeding occurs when
A elution of the analyte is extended over time
B the column is cracked and stationary phase leaks out
C traces of the stationary phase are eluted
D the column breaks during installation and causes personal injury

Answer: traces of the stationary phase are eluted
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