Influence of surfactants on the properties of cellulose derivative-based hybrid materials as chiral stationary phases

Abstract

Due to the regular backbone structure and high chiral recognition ability, polysaccharide derivatives have become most attractive polymer-based candidates for preparation of chiral stationary phases (CSPs) for efficient enantioseparation. However, the traditional polysaccharide-based CSPs usually took up 20 wt% organic contents, implying that only a small proportion of the CSPs had favorable contribution to their enantioseparation properties. To break through this limitation, seven hybrid bead-type CSPs bearing organic components of higher than 30 wt% have been prepared from cellulose tris(3,5-dimethylphenylcarbamates) (CDMPC) and tetraethyl orthosilicate by a sol–gel process. The influence of three types of surfactants on morphology, organic content and particle size of the hybrid bead-type CSPs was carefully investigated. Cetyltrimethyl ammonium bromide (CTAB), a cationic surfactant with a longer alkyl chain, seemed to be favorable to obtain the hybrid CSPs with a high yield and regular morphology. Then their enantioseparation performance was evaluated by high-performance liquid chromatography (HPLC). The hybrid CSPs containing more organic components exhibited stronger enantioseparation power than those with lower organic contents and previous analogue CSP. For some chiral compounds, the hybrid bead-type CSPs exhibited higher enantioselectivity than Chiralpak IB, which is also prepared from CDMPC and one of the most attractive commercialized CSPs nowadays. A higher loading capacity shown by the hybrid CSPs is beneficial for efficient enantioseparation of chiral compounds, especially for preparative purpose.