PACKED-COLUMN SUPERCRITICAL FLUID CHROMATOGRAPHY OF OMEPRAZOLE AND RELATED-COMPOUNDS - SELECTION OF COLUMN SUPPORT WITH TRIETHYLAMINE-MODIFIED AND METHANOL-MODIFIED CARBON-DIOXIDE AS THE MOBILE PHASE

Using standardized chromatographic conditions with respect to carbon dioxide and methanol containing 1% of triethylamine as modifier, the chromatographic behaviour of omeprazole and four of its analogues was investigated on six types of chromatographic support at 40-degrees-C. Superior selectivity was obtained for omeprazole versus its analogues with NH2-modified silica and also good peak symmetry (LiChrosorb and Kromasil). Using the present chromatographic system it is possible to detect and separate the analogues added to omeprazole in the 0.5% (w/w) range within 10 min.