Gas-liquid chromatography is a type of chromatography used for the 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 the sample mixture are split due to the separation between a liquid stationary phase and a gaseous mobile phase that remain 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.
- The length of the GC column is additional compared to high performance liquid chromatography and therefore the most complex sample mixture can be separated with high resolution.
- GLC offers high sensitivity, precision and resolving power compared to other chromatographic methods.
- It can be used with a thermal detector or with a mass detector.
- Sample analysis is very fast, which saves time.
- Very small amounts 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 FID is that the sample that emanates from the detector cannot be recovered.
- The main 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 because it has a constant flow of carrier gas.