Separation of positional isomers by cucurbit[7]uril-mediated capillary electrophoresis

✍ Scribed by Li Xu; Si-Min Liu; Cheng-Tai Wu; Yu-Qi Feng

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 114 KB
• Volume: 25
• Category: Article
• ISSN: 0173-0835
• DOI: 10.1002/elps.200305912

✦ Synopsis

Abstract

A novel macrocyclic molecule, cucurbit[7]uril (CB[7]) was for the first time employed as an additive in capillary electrophoresis (CE). In similarity to other macrocyclic molecules, such as crown ethers, cyclodextrins (CDs) and calixarenes, CB[7] can form inclusion complexes with a variety of guest molecules due to its inner cavity. Thus, it can be used like other macrocyclic molecules to manipulate selectivities in CE. During the running process, CB[7] bears a positive charge under the studied pH range (pH 2.5–7) and can be adsorbed onto the inner wall of a fused‐silica capillary, leading to a reversal of the electroosmotic flow (EOF). Electrophoretic behaviors of nitrotoluene, nitrophenol, nitroaniline, and methylaniline isomers were studied under various conditions. The electrophoretic separations of the isomers can be accomplished with a buffer containing CB[7]. Furthermore, a probable separation mechanism in the presence of CB[7] was also proposed.