When using the SPE cartridge, many kinds of interaction can be produced during the whole process.
1.Non-Polar Interaction The interaction between nonpolar functional group and nonpolar adsorbent on the target chemical compound is called non-polar interaction. This kind of interaction can be better reflected in the polar solvent and especially in water, so it is also called lyophobic interaction. The typical example is the interaction between phthalic acid esters and C18 in the water.
2.Polar Interaction The interaction between polar functional groups on the target chemical compound and the adsorbent is called polar interaction. This kind of interaction can be well reflected in the weak polar solvent or nonpolar solvent.
3.Ion Interaction The interaction between ion functional group on the ion target chemical compound and the functional group with the opposite charges on the adsorbent is called ion interaction.
4.Secondary Interaction As for the reversed silica gel bonding adsorbent, the silicon hydroxyl which remains on the surface of particles can have polar interaction with the polar chemical compound. Also, part of the silicon hydroxyl can have ion interaction with the alkali compound after dissociation. Relate to the non-polar interaction, these interactions are on the sidelines, so we call them secondary interaction.