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Saturday, April 4, 2020

Advantages and disadvantages of gas-liquid chromatography

The gas-liquid chromatography is a type of chromatography used for separation and identification of volatile compounds. The stationary phase consists of small volumes of non-volatile liquid, placed on a finely divided solid inert support, and a mobile phase (carrier gas) is an inert gas such as nitrogen or helium used in gas-liquid chromatography. Gas-liquid chromatography works on the principle of partition. In GC the vaporized molecules of sample mixture fractionated caused by the partition among a liquid stationary phase and a gaseous mobile phase held in the column.
The advantages of gas-liquid chromatography are as follows.
  • Qualitative and quantitative analysis is possible with high sensitivity in gas-liquid chromatography.
  • GC column length is extra as compared with high-performance liquid chromatography and thus the more complex sample mixture can be separate with high resolution.
  • GLC provides high sensitivity, precision and resolution of power compared to other chromatographic methods.
  • We can use it with a thermal detector or with a mass detector.
  • Sampling analysis is very fast so it saves time.
  • Very small quantities of samples are required for analysis.
The disadvantages of gas-liquid chromatography are as follows.
  • The detectors used in GC are destructive.
  • The disadvantage of the FID is that we cannot recover the sample emanating from the detector.
  • The major disadvantage of gas-liquid chromatography is that only volatile samples can be analyzed.
  • In HPLC or TLC we can change the composition of the mobile phase, but in GC, we cannot change the mobile phase since it has a constant flow of carrier gas.

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