RETENTION BEHAVIOR OF VITAMIN-D AND RELATED-COMPOUNDS DURING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

The retention behavior of vitamin D-2-D-5 and provitamin D-2-D-5 are examined using high-performance liquid chromatography. Inclusion chromatography using cyclodextrin as the mobile phase additive in reversed-phase high-performance liquid chromatography is also used for this purpose. Reversed-phase high-performance liquid chromatography is more effective than normal-phase high-performance liquid chromatography in separating these analogs. The addition of methyl-beta-cyclodextrin to the mobile phase is effective in separating the pair of vitamin-D-2 and -D-3 or provitamin-D-2 and -D-3. The separation of the pair of stereoisomeric Cookson-type derivatives of vitamin-D-2 or -D-3 was also examined and found that normal-phase high-performance liquid chromatography is effective for this purpose.