Question

Briefly explain the principles behind normal phase and reverse phase chromatography. Indicate the typical packing material, typical mobile phases, and mechanisms of separation.

Answer 1

In normal phase chromatography the stationary phase is relatively more polar as compared to the mobile phase. The solutes are separated according to polarity. The more polar molecules will be retained on the stationary phase longer and hence have a lower rf value as compared to the less polar components.

In reverse phase chromatography, the mobile phase is more polar than the stationary phase. The less polar components are retained longer on the stationary phase and the more polar components have a higher rf value due to the shorter retention times. They travel more easily with the polar mobile phase.

Thua the separation in both cases is based on the affinity interaction between the analyte components and the phases.

(To tell the packing material and mobile phases I need to know the type of chromatography this is referring to. Column? TLC?)

Please rate