Why does reverse-phase chromatography use a nonpolar stationary phase?

In reverse-phase liquid chromatography, a nonpolar stationary phase is used in conjunction with a polar mobile phase to facilitate the separation of chemical compounds.1

This method relies on the principle that solutes distribute themselves between the two phases based on their relative affinities. By utilizing a nonpolar stationary phase, the technique effectively reverses the order of elution compared to traditional normal-phase chromatography, which employs a polar stationary phase and a less polar mobile phase.231

In this configuration, the interaction between the solutes and the phases is governed by intermolecular forces, such as dispersion forces. Because the stationary phase is nonpolar, it exhibits a higher affinity for nonpolar or less polar solutes, causing them to be retained longer in the column, while more polar solutes are eluted more rapidly by the polar mobile phase. This approach provides a versatile tool for separating mixtures, particularly when the polarity of the solutes varies.312