INDIRECT PHOTODETECTION OF PREGNANOLONE ON A CYCLOBOND COLUMN BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

The chromatographic properties of eight steroids were studied on a Cyc lobond column in order to select those which can be used as markers fo r the indirect photodetection of pregnanolone. Testosterone was shown to be the best compound, enhancing the pregnanolone detection by a fac tor of 6.5 with respect to the direct detection of pregnanolone at 280 nm under the optimum conditions: 0.0085 mM testosterone with methanol -water (65:35) as mobile phase. The influence of the percentage of met hanol and the marker concentration in the mobile phase was studied. Th e models developed previously on a reversed-phase column were successf ully applied and the apparent inclusion constants for progesterone and testosterone in the beta-cyclodextrin cavity were determined. They we re 103 and 2200 l mol(-1) for progesterone and testosterone, respectiv ely, with methanol-water (65:35) and 50 and 780 l mol(-1) with methano l-water (75:35) as mobile phase.