The major difference between gas and liquid chromatography is that gas chromatography uses gas as a mobile phase (nitrogen or helium), while liquid chromatography uses is a liquid (methanol or acetonitrile), which can be either polar or non-polar solvent.
Chromatography is the most commonly used method for the separation of analytes in chemical laboratories for isolation, purification, and analysis as well as in the chemical or pharmaceutical process industry as a part of small and large-scale development. The sample is separated into two components such that the mobile phase is either liquid or gas, and the stationary phase is either solid or liquid.
Some of the most common forms of chromatography are high-performance liquid chromatography, gas chromatography, thin-layer chromatography (TLC or HPTLC), ion-exchange chromatography, and column chromatography.
The key differences between gas chromatography and liquid chromatography are below.
Gas chromatography:
GC is one more extensively used chromatography technique of separation. In this technique the mobile phase is generally a passive gas such as nitrogen, helium or argon which is also known as a carrier gas, the columns are made up with inert materials, packed and capillary columns are used to separate the sample components which are volatile. Capillary columns offer more resolution and are relatively expensive than the other columns.
- Mobile phase in GC is a gas.
- Separation is mainly based on the analytes boiling points.
- Analysis can be done in only in the column.
- Gaseous and volatile compounds can be applied in the separation.
- Due to high temperatures, some components may be degrading.
- Separation of components depends on the boiling point, so it is not very flexible in case of separation optimization.
- The analysis is fast and usually measured in minutes.
- Provide better resolution.
- Solvents that vaporize can be used.
Liquid chromatography:
Liquid chromatography is the most popular technique for separation of the sample mixture on the basis of the interaction between the molecules in the sample with mobile phases and stationary phase. It can be either in a column or on the sheet with a mobile phase and solid support in the form of a stationary phase.
The mobile phase chromatography travels through the stationary phase to bring with different sample components. Interactions between chromatography medium and sample molecules can depend on many factors such as hydrophobicity size, affinity, and charge. Liquid chromatography technology is a sophisticated form which uses pressure with help of the pump, to separate the analyte by the column, is called high-performance liquid chromatography (HPLC). It is now the widely used methods of pharmaceutical analysis for quantitative and qualitative analysis.
- Liquid mobile phase is used in LC.
- Separation of analytes depends on the interaction of the solute with the stationary phase.
- Separation can be done in column or sheet.
- Any soluble compound can separate by LC.
- Generally done at room temperature so that the heat-sensitive compounds can be analyzed safely and no degradation occurs between analyze.
- LC is a relatively time-consuming technique.
- Generally gives a higher or broad peak, which results in less resolution.
- Polar solvents used in LC (water, methanol).
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