An open tubular molecule imprinted polymer (OT-MIP) capillary column has been prepared for chiral separation of ofloxacin enantiomers in CEC. The S-ofloxacin imprinted OT column was fabricated by thermally initiated non-covalent polymerization procedure inside a pretreated and silanized fused silica capillary. The template molecule was incorporated with methacrylic acid (MAA), ethylene glycol dimethacrylate (EDMA) and 4-styrenesulfonic acid (4-SSA) and dissolved in a porogen mixture of ACN/2-propanol (9:1). The separation efficiency of the 4-SSA MIP column was found quite better than that of the MIP column without 4-SSA. It has been demonstrated that our OT-MIP column can separate ofloxacin enantiomers with excellent chiral separation efficiency after tuning the various chromatographic conditions. The optimized chromatographic eluent was 85:15, v/v%, ACN/60 mM sodium acetate at pH 7. The separation efficiency and selectivity of chiral separation of this study were far better than those obtained by previous methods for chiral separation of R- and S-ofloxacin.

A generalized preparation procedure of open tubular (OT) molecule imprinted polymer (MIP) columns is proposed for a number of templates with acidic functionality such as profen drugs and others. The template (S-enantiomer) was mixed with methacrylic acid, ethylene glycol dimethacrylate and 4-styrenesulfonic acid, dissolved in a porogen mixture of ACN/2-propanol (9/1), and incubated in a pretreated and silanized fused silica capillary by the thermal non-covalent polymerization procedure. The whole preparation procedure was exactly the same for all the MIP capillaries except for the selection of template. Nevertheless, the morphologies of the MIP layers were markedly variant depending upon the choice of template. The separation efficiency of each OT-MIP column for chiral separation of R- and S-enantiomers was examined and tuned to obtain the best separation efficiency by changing the chromatographic parameters such as eluent composition and pH. Different optimized conditions were obtained for different OT-MIP columns. Nevertheless, a unified eluent could be used to obtain still quite satisfactory results. Non-chiral separation of the MIP columns were also examined in the unified eluent with two sets of test mixtures, that is, a mixture of alkylbenzenes and a mixture of small polar solutes. The chiral and non-chiral separation of this study resulted in very good separation efficiencies. This work is the very first study for the generalization of preparation of OT-MIP columns for a number of templates.

A new stationary phase has been prepared by attaching a new chain transfer agent on silica particles followed by reversible addition-fragmentation chain transfer polymerization. Porous silica particles were reacted with 3-chloropropyltrimethoxysilane followed by sodium diethyl dithiocarbarmate. The silica particles were then allowed to undergo radical polymerization with styrene. The phase had improved ligand morphology to show better separation performance than that of the conventional C18 phase.

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