Gas Solid Chromatography Vs Gas Liquid Chromatography: What Is The Difference?

Gas chromatography is the most widely used form of chromatography in analytical chemistry for separating and analyzing compounds that can be vaporized without decomposition. Gas chromatography is used to separate complex mixtures of different molecules based on their physical properties such as polarity and boiling point. The other uses of gas chromatography include:

  • Testing purity of a substance
  • Separating the different component of a mixture
  • Identification of compounds
  • Preparation of pure compounds from a mixture

In gas chromatography, the components of a sample are dissolved in a solvent and vaporized in order to separate the analytes by distributing the sample between two phases, stationary phase and mobile phase. The mobile phase is a chemically inert gas that serves to carry the molecules of the analyte through the heated column. The stationary phase is either a solid adsorbent or a liquid on an inert support.

All forms of chromatography involve a stationary phase and a mobile phase. In this regard, Gas chromatography is mainly divided into two main types, that is, Gas liquid chromatography and Gas solid chromatography. In both methods, gas is used as mobile phase and either solid or liquid used as stationary phase.

Gas Solid Chromatography

In gas solid chromatography, it is the interaction between the gaseous sample (the mobile phase) and the stationary phase comprising of an active solid adsorbent powder which causes the separation of different constituents. Usually, the adsorbent powder is filled in an open tube.

The active solid support provides an adsorbent surface on which selective adsorption and desorption of the volatile components takes place. Modern columns are usually packed with porous polymers or materials such as activated carbon, molecular sieves, silica and aluminum powder etc. 

Gas-solid chromatography is used for applications that can broadly be characterized as those difficult to achieve by gas-liquid chromatography above ambient temperatures. These include the separation of gases, solvents and volatile hydrocarbons and halocarbons.

Characteristic of Gas Solid Chromatography

  • It is an adsorption chromatography technique.
  • In gas solid chromatography, the stationary phase is in the solid state whereas the mobile phase is in the gaseous state.
  • The stationary phase is applied on the inner wall of the column as a solid compound.
  • It uses packed columns.
  • The retention time (Rf) is comparatively long in gas solid chromatography.
  • The GSC can be used at high temperatures.
  • The stationary phase of gas solid chromatography is stable.
  • No liquid phase is involved in gas solid chromatography.

Gas Liquid Chromatography

In gas-liquid chromatography, it is the interaction between the gaseous sample (the mobile phase) and a standard liquid (the stationary phase), which causes the separation of different constituents. The stationary phase is either a polar or nonpolar liquid which in the case of capillary column, coats the inside of the column, or is impregnated onto an inert solid that is then packed into the gas chromatography column.

Gas-liquid chromatography (GIC) is one of the most effective and widely applied methods for the separation, identification and quantitative analysis of complex multi-component mixtures.

Characteristics of Gas Liquid Chromatography

  • It is a partition chromatography technique.
  • In gas liquid chromatography, the stationary phase is in the liquid state whereas the mobile phase is in the gaseous state.
  • The stationary phase is applied on the inner wall of the column as a thin liquid film.
  • It uses capillary columns.
  • The retention time (Rf) is comparatively short in gas liquid chromatography.
  • The GLC cannot be used at high temperatures.
  • The stationary phase of the gas liquid chromatography is unstable.
  • At least one liquid phase is involved in gas liquid chromatography.

Difference Between Gas Solid Chromatography And Gas Liquid Chromatography In Tabular Form

BASIS OF COMPARISONGAS SOLID CHROMATOGRAPHYGAS LIQUID CHROMATOGRAPHY
DescriptionIt is an adsorption chromatography technique.  It is a partition chromatography technique.  
Stationary & Mobile PhaseIn gas solid chromatography, the stationary phase is in the solid state whereas the mobile phase is in the gaseous state.  In gas liquid chromatography, the stationary phase is in the liquid state whereas the mobile phase is in the gaseous state.  
Stationary Phase ApplicationThe stationary phase is applied on the inner wall of the column as a solid compound.  The stationary phase is applied on the inner wall of the column as a thin liquid film.  
ColumnIt uses packed columns.  It uses capillary columns.  
Retention TimeThe retention time (Rf) is comparatively long in gas solid chromatography.  The retention time (Rf) is comparatively short in gas liquid chromatography.  
Use At High TemperatureThe GSC can be used at high temperatures.  The GLC cannot be used at high temperatures.  
Stationary Phase StabilityThe stationary phase of gas solid chromatography is stable.  The stationary phase of the gas liquid chromatography is unstable.  
Liquid PhaseNo liquid phase is involved in gas solid chromatography.  At least one liquid phase is involved in gas liquid chromatography.  

Applications of Gas Chromatography

  • Gas chromatography is used extensively in forensic science
  • Gas chromatography is used to calculate the content of a chemical product or measuring toxic substances in soil, air or water.
  • It is used in the analysis of performance-enhancing drugs in athlete‚Äôs urine samples
  • Analysis of air-borne pollutants
  • Used in analysis of fatty acids, flavor compounds and drugs.
  • Used in analysis of toxic compounds and solvents.