Use of calix[4]arene to separate positional isomers in capillary electrophoresis

The use of water-soluble calixarene, p-sulfonic calix[4]arene, in capillary electrophoresis, was reported. Successful separations of positional isomers of nitrophenol, benzenediol and aminophenol were obtained with the addition of p-sulfonic calix[4]arene to the running buffer. Efficiency up to 3.0×105 plates/m was achieved. The influence of the calixarene concentration was studied and it was found that the resolution increased with the increasing calixarene concentration. The interaction of solutes with calixarene was also discussed.