CHEMOMETRIC CATEGORIZATION OF OCTADECYLSILYL BONDED-PHASE SILICA COLUMNS USING TEST MIXTURES AND CONFIRMATION OF RESULTS WITH PHARMACEUTICAL COMPOUND SEPARATIONS

The chromatographic properties of seventeen commercial octadecylsilyl phases were characterized in order to determine column similarities an d differences that would aid in column selection for method developmen t, choice of an alternate column and method ruggedness testing. Chroma tographic test mixtures from the literature were used to probe the hyd rophobicity, free silanol interactions, trace metal activity, and shap e selectivity of these columns. Principal components and cluster analy sis methods were used to categorize the columns into groups that tende d to display similar chromatographic properties. The validity of the g roups was tested with mixtures of pharmaceutical compounds under a var iety of mobile phase conditions. In general, columns that were categor ized together from the test mixture analysis showed similar behavior f or the analysis of the pharmaceutical compound mixtures.