Chromatography is a separation technique in which the mixture to be separated is dissolved in a solvent and the resulting solution, often called the mobile phase, is then passed through or over another material, the stationary phase. The process of chromatography requires a sample extract to be passed through a gas, liquid or a super critical fluid. This is the mobile phase, which ends in a transition to a stationary phase. The different phases of the process are set up in such a way to differentiate and extract the different components of the sample at varying degrees making it possible for us to identify the components. The separation actually happens in the stationery phase when the start creeping and traveling through the phases.
In order to prepare the set up for chromatography columns are used. They are chosen on the basis of their theoretical and practical optimum loading capacity. Aside from this solvents are used, which will dissolve the sample making it possible for the different constituents to be separated. Fraction collectors or marked chromatograms are used to keep record of where and when the separation occurs for each of the different constituents. “The special packing techniques necessary for both preparative gas chromatography and liquid chromatography columns are described including both the radial and axial compression techniques. Procedures such as recycling, together with the moving bed and simulated moving bed systems are discussed in detail and some examples of the use of the moving bed system included.” (Scott, 2007)