Improved testing procedures for comprehensive evaluation of reversed phase HPLC columns

The ever increasing number of commercially available reversed phase columns with which the analyst is confronted can cause problems in columns selection, moreover these columns provide great variety in their chromatographic selectivity. These and the non standard test procedure used by the column manufactures and packing companies cause further confusion. This work describes comprehensive test procedure that was used to evaluate reversed phase columns in terms of their kinetic and thermodynamic properties. The quality of column packing process and therefore column efficiency and the suitability of HPLC system for separation were evaluated in the kinetic part of the test procedure. In the thermodynamic part reversed phase columns were evaluated for their hydrophobicity, silanophilic activity and shape selectivity in an unbuffered eluant and were evaluated for metal activity and cation exchange capacity in abuffered eluant. The work discusses the repeatability of best procedures and the effect of temperature and eluant composition evaluation. During this work a total of 38 C₈ and C₁₈ reversed phase columns were used. A simple improved procedure for a comprehensive evaluation of C8 and C18 reversed phase HPLC columns has been investigated. The column evaluation process is highly reproducible and is not significantly influenced by slight changes in column temperature and mobile phase composition using the improved procedures on reversed phase columns able the analyst to characterize and classify these columns according to their efficiency and validity for the analysis of different classes of compounds.

Keywords: Reversed phase columns, Testing procedure for HPLC columns,stationary phase evaluation, HPLC, column kinetic and thermodynamic test.

* Corresponding Author, Farid R. Zaggout.