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Gas Chromatography problems


  • 1. Which of the statements is correct?

  • Options
  • 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
  • Discuss
  • 2. What does the retention factor, k', describe?

  • Options
  • A. The distribution of an analyte between the stationary and the mobile phase
  • B. The migration rate of an analyte through a column
  • C. The velocity of the mobile phase
  • D. All of these
  • Discuss
  • 3. Sample retention in the column is measured by

  • Options
  • A. retention time
  • B. retention factor
  • C. retention index
  • D. all of these
  • Discuss
  • 4. Sample injection is considered successful if

  • Options
  • A. all of the sample in the injector has been added to the column
  • B. the sample is concentrated at the start of the column
  • C. the sample is spread evenly along the column
  • D. the sample is homogenously spread along the column
  • Discuss
  • 5. What are the benefits of decreasing the column internal diameter?

  • Options
  • A. Increased sample capacity
  • B. Increased resolution
  • C. Reduced risk of column overloading
  • D. All of the above
  • Discuss
  • 6. Derivatisation of a sample is carried out to

  • Options
  • A. reduce polarity of the analytes
  • B. increase the detector response
  • C. increase volatility of the analytes
  • D. all of the above
  • Discuss
  • 7. In column switching chromatography

  • Options
  • 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
  • Discuss
  • 8. Resolution is proportional to the

  • Options
  • 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
  • Discuss
  • 9. The column is heated to

  • Options
  • A. prevent analyte condensation within the column
  • B. control elution of the different analytes
  • C. reduce band broadening to get sharper peaks
  • D. all of these
  • Discuss
  • 10. Which of the following detectors give mass flow-dependent signals?

  • Options
  • A. Electron capture detector
  • B. Field ionisation detector
  • C. Thermal conductivity detector
  • D. All of the above
  • Discuss

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