Comparison Of Resolution Of Chiral Stationary Phases Of?-cyclodextrin (Phenyl Carbamate) In Multimodal Mobile Phase Compisitions

During the past two decades,chirality has been one of the most popular topics in medicine,agrochemicals,foods and functional materials.High-performance liquid chromatography chiral stationary phase(CSP)method has advanced to become the most powerful method not only for analysing enantiomers but also for obtaining them in optically pure form.Among all the chiral selectors explored in literature,?-cyclodextrins(?-CDs)and their derivatives marked by their cavity structure are the most widely used ones in the resolution of racemic compounds.?-CD-CSP1 and ?-CD-CSP2 were prepared using ?-CD and HP-?-CD as raw materials,4-chlorophenyl isoyanate and phenyl isocyanate as derivative reagents respectively,silica gel as support,and ?-(triethoxysilyl)propyl isoyanate as the bonding reagents.The chiral resolution abilities of the obtained bonded ?-CD CSPs were evaluated through enantioseparation of more than 40 racemates under the HPLC normal phase mode,reversed phase mode,adding acid or base as mobile phase regulator and polar organic phases.The results show that the two self-made CSPs exhibit great chiral recognition ability,and a variety of chiral drugs with acid or base properties can achieve baseline separation.In the polar organic phase mode,the splitting attempt is complementary to the normal and reverse phase.In general,the resolution of CSP1 is better than that of CSP2 when the mobile phase condition is certain.4-Chlorophenycarbamate ?-CD derivative was achieved using ?-CD as raw material and4-chlorophenyl isoyanate as derivative reagent.Then the derivative was coated on the novel poly dopamine silica gel to obtain ?-CD-CSP3.Under normal conditions,the resolution of the stationary phase was investigated by adjusting the content of isopropanol and changing the type of alcohol.?-CD-CSP3 has a certain ability of chiral separation for the 23 samples.The experimental results show that the factors affecting the separation and retention time of the enantiomers are not only the structure of the sample itself,but also the volume fraction of isopropanol in the mobile phase and the three-dimensional structure of the alcohols.It is significant to choose the different sterically hindered alcohols as the mobile phase modifier for the splitting range of the chiral column.