Analytical Instrumentation Questions and Answers – Gas Chromatography

This set of Analytical Instrumentation Multiple Choice Questions & Answers (MCQs) focuses on “Gas Chromatography”.

1. For the separation of which of the following substances, Gas-solid chromatography is being used?
a) Thermally stable organic components
b) Volatile organic components
c) Thermally stable inorganic components
d) Low molecular weight gaseous species
View Answer

Answer: d
Explanation: Gas-solid chromatography is used for the separation of low molecular weight gaseous species. Its application is limited because of semi-permanent retention of the analyte.

2. Which of the following is not a feature of carrier gas used in gas chromatography?
a) It must be chemically inert
b) It should be suitable for the detector employed
c) It should not be completely pure
d) It should be cheap
View Answer

Answer: c
Explanation: It should be highly pure. Further, it should be readily available and non-inflammable.

3. Which of the following is the disadvantage of hydrogen, which can be used as carrier gas in gas chromatography?
a) Dangerous to use
b) Expensive
c) Reduced sensitivity
d) High density
View Answer

Answer: a
Explanation: Hydrogen is dangerous to use. It has better thermal conductivity and lower density.
advertisement
advertisement

4. Which of the following is the disadvantage of helium, which can be used as carrier gas in gas chromatography?
a) Dangerous to use
b) Expensive
c) Reduced sensitivity
d) High density
View Answer

Answer: b
Explanation: Helium is expensive. Its advantages are that it has low density and it allows greater flow rates.

5. Which of the following is the disadvantage of nitrogen, which can be used as carrier gas in gas chromatography?
a) Dangerous to use
b) Expensive
c) Reduced sensitivity
d) High density
View Answer

Answer: c
Explanation: Nitrogen has reduced sensitivity. It is still one of the commonly used carrier gas in gas chromatography.
Sanfoundry Certification Contest of the Month is Live. 100+ Subjects. Participate Now!

6. Slow injection of large samples leads to band broadening and loss of resolution.
a) True
b) False
View Answer

Answer: a
Explanation: Slow injection of large samples leads to band broadening and loss of resolution. Hence, for desired column efficiency, samples should not be too large.

7. In which of the following methods are liquid samples injected into the column in gas chromatography?
a) Gas tight syringe
b) Micro-syringe
c) Rotary sample valve
d) Solid injection syringes
View Answer

Answer: b
Explanation: Liquid samples injected into the column in gas chromatography using micro-syringe. Syringes of various capacities are available.
advertisement

8. What must be done to the solid samples for it to be introduced into the column without using solid injection syringes in gas chromatography?
a) Introduced in hot-zone of the column
b) Dissolved in volatile liquids
c) Introduced using rotary sample valve
d) Introduced using sampling loops
View Answer

Answer: b
Explanation: Solid samples must be dissolved in volatile liquids for introducing it into the column. They can be introduced directly using solid injection syringes.

9. Which of the following is the commonly used support material for the packed column in gas chromatography?
a) Glass
b) Metal
c) Diatomaceous earth
d) Stainless steel
View Answer

Answer: c
Explanation: Diatomaceous earth is the commonly used support material for the packed column in gas chromatography. The columns could be made of glass or metal.
advertisement

10. Which of the following is the advantage of a straight packed column?
a) It can be packed uniformly
b) It can be repacked easily
c) It is compact
d) It is easier to heat it evenly
View Answer

Answer: c
Explanation: The advantage of the straight column is that it can be repacked easily. It is not compact in size.

11. Which of the following is the disadvantage of coiled or helical shaped packed chromatographic column?
a) It cannot be packed uniformly
b) It cannot be repacked easily
c) It is not compact
d) It is not easy to heat it evenly
View Answer

Answer: b
Explanation: The disadvantage of coiled or helical shaped packed chromatographic column is that it cannot be repacked easily. It is compact in size and can easily be heated in an even manner.

12. Capillary columns are open tubular columns constructed from which of the following materials?
a) Glass
b) Metal
c) Stainless steel
d) Fused silica
View Answer

Answer: d
Explanation: Capillary columns are constructed using fused silica. It is a very high purity glass.

13. Sample injection port must be maintained at a temperature at which rapid vapourisation occurs but thermal degradation does not occur.
a) True
b) False
View Answer

Answer: a
Explanation: Sample injection port must be maintained at a temperature at which rapid vapourisation occurs but thermal degradation does not occur. The column is maintained at a different temperature.

14. Which of the following is not a desirable feature of the ovens used in gas chromatography?
a) It must have a fast rate of heating
b) Power consumption should be kept low
c) It must have maximum thermal gradients
d) It should have proper insulation
View Answer

Answer: c
Explanation: The ovens used in gas chromatography must have maximum thermal gradients. The temperature must be uniform over the whole column.

15. Given below is the block diagram of gas chromatography. Identify the unmarked component.
Sample injection system is unmarked component in block diagram of gas chromatography
a) Pumping system
b) Pressure regulator
c) Flow regulator
d) Sample injection system
View Answer

Answer: d
Explanation: The unmarked component is syringe. Hence, the answer is sample injection system. It is for the introduction of sample into the flowing gas stream.

Sanfoundry Global Education & Learning Series – Analytical Instrumentation.

To practice all areas of Analytical Instrumentation, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

advertisement
advertisement
Subscribe to our Newsletters (Subject-wise). Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

Youtube | Telegram | LinkedIn | Instagram | Facebook | Twitter | Pinterest
Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

Subscribe to his free Masterclasses at Youtube & discussions at Telegram SanfoundryClasses.