Strong cation exchange-type chiral stationary phase for enantioseparation of chiral amines in subcritical fluid chromatography.

摘要: A new strong cation exchange type chiral stationary phase (SCX CSP) based on a syringic acid amide derivative of trans-(R, R)-2-aminocyclohexanesulfonic was applied to subcritical fluid chromatography (SFC) for separation various basic drugs and their analogues. Mobile systems consisting aliphatic alcohols as polar modifiers broad range amines with different substitution patterns lipophilicity were employed evaluate the impact SFC retention selectivity characteristics. The observed results point existence carbonic carbamic salts formed consequence reactions occurring between carbon dioxide, alcoholic amine species present in sub/supercritical medium, respectively. Evidence is provided that these are essential affecting ion strongly acidic selector units analytes, following well-established stoichiometric displacement mechanisms. Specific trends when types used additives. While ammonia gave rise formation most eluting salt species, simple tertiary consistently superior levels enantioselectivity. Furthermore, characteristics investigated by systematic variation modifier content temperature. Different effects additives interpreted terms changes relative concentration transient ionic contributing analyte elution, ammonia-derived being depleted at elevated temperatures decomposition. Additionally, an effort optimize enantiomer conditions selected organic modifier, temperature, flow rate active back pressure also investigated.