About columns used in HPLC analysis
C18 reveals the typical characteristics on the alkyl group - non-polar and ionically inert in most typical ailments. Retention from a C18 stationary period comes from weak van der Waals intermolecular power that pulls hydrophobic compounds. C18 along with other alkyl phases such as C8 and C4 constitute the most basic style of reverse section HPLC.f