Separation of positional isomers by cucurbit[7]uril-mediated capillary electrophoresis.
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.
Xu
Li
L
Department of Chemistry, Wuhan University, Wuhan, P.R. China.
Liu
Si-Min
SM
Wu
Cheng-Tai
CT
Feng
Yu-Qi
YQ
D001952:Bridged-Ring Compounds / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000379:methods*; D007093:Imidazoles / Q000737:chemistry*; D007536:Isomerism; D008279:Magnetic Resonance Imaging; D013056:Spectrophotometry, Ultraviolet; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils
D001952:Bridged-Ring Compounds; D007093:Imidazoles; C456276:cucurbit(7)uril; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils