CHROMATOGRAPHIC CLASSIFICATION OF COMMERCIALLY AVAILABLE REVERSE-PHASE HPLC COLUMNS

The ever-increasing number of commercially available reversed phases w ith which the analyst is confronted can cause problems in column selec tion. These and the non-standard test procedures used by the column ma nufacturers and packing companies cause further confusion. In order to independently compare and contrast a range of well established C18 st ationary phases, we have performed a modified column characterization approach, based on Tanaka's methodology, on thirty commonly used phase s in our laboratory. These results have been evaluated and presented i n various formats as Principal Component Analysis, Cluster Analysis, T abular Format and Radar Plots in order to assist in observing similari ties and differences between phases. The results indicate that, while no two phases are exactly the same (with the exception of ''me-to'' cl ones), it is possible to characterize phases into different classes ba sed on their chromatographic performance against selected test probes. The paper illustrates the similarities and differences between these phases. The column characterization described in the paper can form th e basis of a rational column selection protocol by either careful matc hing of the appropriate column characteristics to the analyte's physic o-chemical properties or by a systematic evaluation of columns from ou r various categories.