1. Principle

In any chromatographic method, separations are based on the distribution of solutes between two immiscible phases, one stationary, called the stationary phase, the other moving, called the mobile phase (figure 1 ). In this way, the operation of dividing the species to be separated between the two phases is automatically repeated a very large number of times for each species in a continuous manner, enabling the exploitation of minimal differences in the species distribution coefficient between the two phases. While the mobile phase tends to carry the species to be separated along with it, the stationary phase tends to delay them, all the more so as the interactions involved are more intense, numerous and energetic. The result is that most analytes have different speeds of movement, lower than that...