Comparative study of test methods for reversed-phase columns for high-performance liquid chromatography

Column selection in reversed-phase liquid chromatography (RPLC) is still no t a straightforward process. A number of tests to characterise and classify RPLC columns have been suggested. Several tests are already applied in lab oratory practice, while others are under development. The results of the va rious tests, however, are not always qualified to describe the properties o f columns for RPLC. In this study different tests for RPLC-columns are stud ied and compared, viz. the Engelhardt, Tanaka, Galushko and Waiters tests. The column descriptors hydrophobicity and silanol activity are investigated in particular. The tests are studied using approximately 20 silica, alumin a and polymer based C-8- and C-18-columns. Hydrophobicity data from the tes ts generally were good and interchangeable between the tests resulting in a column classification that is independent of the applied test. It appears that buffering of the eluent is mandatory for adequate testing of column si lanol activity. In contrast with the high-quality hydrophobicity data, the silanol activity results of the various tests differ significantly. As a co nsequence column classification with respect to silanol activity depends co nsiderably on the applied test method. (C) 1998 Elsevier Science B.V. All r ights reserved.