Chromatography – A Brief Introduction
Chromatography is a method widely used in the separation of different compounds, solid and liquid. This method is very helpful in segregating and purifying various components of mixtures, which when separated can be analyzed individually. The chromatography process is a very simple method of separating compounds using a solid as well as liquid phase. Silica gel, alumina oxide is mainly used as the solid phase, which adsorbs all the unwanted particles as well as all kinds of impurities. When the mixture passes through the mobile phase, then only the required compounds move forward while the unwanted components of the main mixture are left behind.
Silica Gel for Column Chromatography:
The main characteristics of Silica Gel are that it is a good adsorbent and has a very large surface area. These two characteristics help it in adsorbing small impurities and allow only the desired molecules to pass through. This property works towards making Silica Gel a highly popular desiccant and adsorbent. Silica Gel finds use in almost all kinds of chromatography. These include analytical, preparative, process and gravity chromatography. In all these forms of chromatography, the solid or stationary phase (Silica Gel) effectively adsorbs the different components at various levels to achieve higher levels of purification. Described below are some of the chromatography methods, which make effective use of Silica Gel as an adsorbent.
- Analytical chromatography:
Analytical chromatography, as the name suggests, is conducted to have a detailed analysis of the various components of mixtures. Analytical chromatography is mostly done when only small quantities of substances have to be separated for further analysis. This form of chromatography also finds use in measuring the different ratios of analytes present in the concerned mixtures.
- Preparative chromatography:
Preparative chromatography is another important form of chromatography wherein the different components of any given mixture are mainly separated for more advanced purposes. After being separated using the Silica gel solid phase and the liquid phase, the various components are subjected to advanced analysis. Preparative chromatography also finds use in many purification processes as well.
- Process chromatography:
Process chromatography is mainly used in industrial and business establishments for the separation and purification of mixtures on a large scale and advanced basis.
- Gravity Chromatography:
The column chromatography method, which makes use of the gravitational force instead of air pressure to make the mixture move down the vertical chromatography Column, is known as gravity chromatography.