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Currently, NPCE/CEC technology has been successfully used for the separation of protein, peptide, chiral drugs and metal ion, etc. The separation mechanisms may involve hydrophobic interaction, electrostatic effect, ion exchange, etc.
Compared to traditional CE technology, these NPs can provide new interaction sites with the analytes. Consequently, the technology can be used for the separation of both charged and neutral compounds. In addition, exchanging the type of NPs can realize the conversion of separation mode, so the tedious preparation of a column can be eliminated and the reproducibility between column and column increase.
Polyhedral oligomeric silsesquioxane (POSS) is a novel type of cage-like sisesquioxane, which embodies a true inorganic-organic hybrid architecture containing an inner inorganic framework made up of silicon and oxygen and surrounded by organic functional groups. It usually refers to the structure with the empirical formula Rn(SiO1.5)n (n≧integer 4).Currently, the most studied is n=8.Wu et al have selected POSS reagent containing methacrylic group as cross-linker and long carbon chain quaternary ammonium as the functional monomer for the synthesis of monolithic capillary columns with reverse phase and strong anion exchange mode, via thermal initiated free radical polymerization. Different analytes such as alkylbenzene, peptides and standard proteins can be baseline separated on this hybrid column.
Chiral separation is an important branch in the field of separation science, and so developing simple and effective methods for the chiral separation via choosing an appropriate chiral reagent is essential. Among them, cyclodextrin and its derivatives are the most widely used. If pure CDs are used as additive to separate enantiomers, the amount is usually large to achieve satisfactory result. Thus in recent years, the researchers have been focusing on bonding CD on the surface of nanoparticles, which may greatly reduce the amount of chiral selectors. Yang et al have successfully synthesized β-CD modified gold nanoparticles, which were used as pseudostationary for the separation of racemic compounds including amino acids, representative chiral drugs, and the result showed that these compounds could be baseline separated , while the amount of CDs were greatly reduced. |