A Global Approach to HPLC Column Selection Using Reversed-Phase and HILIC Modes: What To Try When C18 Doesn't Work

Experimental data are presented to help understand high performance liquid chromatography column retention in a way that should make column selection and method development proceed faster when initial results with C18 columns are disappointing. Three stationary phases having widely different surface properties are profiled with aqueous-organic mobile phases using a series of simple probe compounds that also represent a wide range of chemical characteristics. From these global results, it is possible to draw conclusions about the applicability of certain phase types toward classes of compounds and offer general rules for selecting a column when C18 does not work. Such an approach can replace the trial-and-error method and does not require an advanced understanding of retention mechanisms or complex mathematical treatments. This approach should be particularly helpful when trying to separate polar or ionic compounds that are not easily retained on traditional reversed-phase columns. [PUBLICATION ABSTRACT]