Principles of HPLC
Figure 1. Components of an HPLC instrument
As it is shown in Figure 1, this method uses a column which is filled with fine beads that form the stationary phase and a solvent, which is known as mobile phase and, as the name suggests, moves over the column due to pressure that is generated by the pump.
When a mixture of analytes A, B and C pass through the column, they will interact differently with the stationary phase based on their property. Analytes that interact the least with the stationary phase will move the fastest (A). In contrast, analytes that interact the most with the stationary phase will stay longer in the column (C) and reach the detector last.
In chromatography, compounds that alike attract each others. Polar compounds will be most attracted to other polar compounds and non-polar compounds will be most attracted to other non-polar compounds.