1. Chromatographic process

1.1 Comparison of column and planar liquid chromatography

The most important part of a chromatograph is the stationary phase/mobile phase assembly. Every chromatographic operation involves :

• moving the mobile phase;

• injection of solutes ;

• the chromatographic process ;

• solute detection.

In high-performance liquid chromatography (HPLC), the mobile phase is pumped into the column, with the operator in control of the flow rate. Injection is performed by a loop valve without interrupting the pump flow, and the solutes are injected into a balanced system. The chromatographic process takes place but is not visible...