Biochemistry MCQ Quiz Hub

1. What is the typical internal diameter of fused silica capillary columns?
0.2-0.3 mm
0.3-0.5mm
0.5-1.0 mm
1.0-2.0 mm

2. Resolution is proportional to the
number of theoretical plates in a column
square root of the number of theoretical plates in a column
square of the number of theoretical plates in a column
cube root of the number of theoretical plates in a column

3. In column switching chromatography
compounds trapped on one column are eluted to another column
one column is removed and replaced by another
the flow to the column is switched on and off repeatedly
any of the above

4. Which of the following detectors give mass flow-dependent signals?
Electron capture detector
Field ionisation detector
Thermal conductivity detector
All of the above

5. Headspace analysis is carried out in order to
analyse volatile compounds from solid or liquid samples
determine the psychological state of the tutor
analyse the column contents ahead of the sample
determine non-volatiles

6. Split injection is carried out by
splitting the sample into smaller portions to inject sequentially
splitting the sample into smaller portions to inject at the same time through parallel ports
splitting off some of the sample so that it does not enter the column
none of the above

7. What does the retention factor, k', describe?
The distribution of an analyte between the stationary and the mobile phase
The migration rate of an analyte through a column
The velocity of the mobile phase
All of these

8. Theoretical plates are used to
estimate the efficiency of a column
determine the thickness of the stationary phase
measure the distribution of the analyte between mobile and stationary phases
None of the above

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

10. The column is heated to
prevent analyte condensation within the column
control elution of the different analytes
reduce band broadening to get sharper peaks
all of these

11. What are the benefits of decreasing the column internal diameter?
Increased sample capacity
Increased resolution
Reduced risk of column overloading
All of the above

12. Sample retention in the column is measured by
retention time
retention factor
retention index
all of these

13. Which of the following are not used as stationary phases in a GC column?
Polysiloxanes
Silica
Cyclodextrins
None are used as stationary phases

14. Sample injection is considered successful if
all of the sample in the injector has been added to the column
the sample is concentrated at the start of the column
the sample is spread evenly along the column
the sample is homogenously spread along the column

15. Which of the following is not used for detection in GC?
Infrared spectroscopy
NMR
Flame ionisation
Electrical conductivity

16. The GC trace obtained after an experiment is called a
chromatograph
chromatogram
chromatophore
graph

17. Which of the following detectors give concentration-dependent signals?
Electron-capture detector
Thermal conductivity
Infra-red detector
All of these

18. What useful information can be found from a Van Deemter plot?
The selectivity factor
Optimum mobile phase flow rate
Optimum column temperature
Optimum column length

19. Derivatisation of a sample is carried out to
reduce polarity of the analytes
increase the detector response
increase volatility of the analytes
all of the above

20. Which of the statements is correct?
Gas chromatography is used to analyse gases
Gas chromatography is used to analyse solids
Gas chromatography is used to analyse gases, solutions and solids
All of the above

21. A retention gap is placed between the injector and the front of the column to
retain contaminants and prevent them from reaching the column
retain the sample and release it gradually to the column
prevent backflush of the injected solution
all of the above

22. Helium is generally preferred as carrier gas over nitrogen and hydrogen because
it is inert
it has a lower viscosity
it doubles up as a party gas for balloons and funny voices
all of above

23. Column bleeding occurs when
elution of the analyte is extended over time
the column is cracked and stationary phase leaks out
traces of the stationary phase are eluted
the column breaks during installation and causes personal injur

24. Doubling the column's length increases resolution by a factor of
(2)0.5
2
3
4

25. Sample injection is considered successful if
the sample is homogenously spread along the column
all of the sample in the injector has been added to the column
the sample is spread evenly along the column
None

26. Which of the following gases is unsuitable for use as a GC carrier gas?
Nitrogen
Helium
Oxygen
All of the above