New stationary phase based on beta-cyclodextrin for normal-phase HPLC group-separation of organic nitrates

The synthesis of a beta-cyclodextrin-silica normal-phase (NP)-liquid chroma tography (LC) stationary phase is reported. Silica gel was modified with (3 -bromopropyl)trimethoxysilane to a 3-bromopropyl-silica that was reacted wi th beta-cyclodextrin, resulting in a beta-cyclodextrin-silica. To prove its usefulness in group-separation of organic nitrates among others, a mixture of three groups of organic nitrates was separated. The results are compare d with those obtained on a nitrated polyol-silica that has recently been re ported. The alkyl dinitrates exhibt higher retention relatively to alkyl mo nonitrates on the new phase. This allows to cut the LC fractions in a way t hat the alkyl mononitrates and phenylalkyl nitrates appear in one fraction and the dinitrates in a second one without any overlap of the two fractions .