The poor peak shape encountered for amines in reversed phase high performance liquid chromatography (RPLC) is widely recognized. In order to improve chromatographic efficiency, the mechanism of the broadening must be understood. In addition to the silanol groups on the support surface, metal sites have been implicated as possible adsorption sites for amines. We have investigated the relative role of metallophilic and silanophilic interactions in the non-ideal behavior of amines and proteins. Stainless steel frits appear to have a deleterious effect on column efficiency via both mechanical and chemical interactions. The use of stainless steel meshes or screens is recommended. The residual metal sites on the support material have been found to play an insignificant role in solute retention or peak broadening. Minimization of silanophilic interactions is therefore the key to increasing efficiency in the separation of basic amines.