CAPILLARY ELECTROCHROMATOGRAPHY AS A METHOD DEVELOPMENT TOOL FOR THE LIQUID-CHROMATOGRAPHIC SEPARATION OF DUP-654 AND RELATED SUBSTANCES

Capillary Electrochromatography (CEC) offers a rapid, economical, and efficient means for resolving nonionic compounds in the reversed phase mode on octadecylsilane (ODS) columns. A CEC optimization on a Hypers il ODS capillary column was employed to identify a suitable mobile pha se for the pressure-driven (reversed phase ODS) separation of the anti -inflammatory 2-phenylmethyl-1-naphthol (DUP 654), and its related sub stances. The proportions of mobile phase modifiers methanol, acetonitr ile, and water as well as pH were employed as variables in a stacked m ixture design. Comparable response surface profiles were obtained for the CEC separations at pH 4 and pH 8. However, subtle differences were evident in the quality of separations obtained in the liquid chromato graphic (LC) mode when using a specially-prepared column packed with e xactly the same stationary phase as used in the CEC experiments. A map ping of the response surface for separations on a commercially availab le Hypersil ODS LC column revealed obvious differences, The difference s indicate that the transfer of ODS based separation methods between C EC and LC involves more than simply transferring the conditions from o ne mode to the other.