Studies on mechanism of acetonitrile-salts stacking method in capillary electrophoresis

Acetonitrile-salt stacking method (ASS), as a new developed on-line stacking method in capillary electrophoresis, is suitable for stacking and analyzing low concentration analytes, which contain high concentrations of salts, and it has the huge practical potential in bio-analysis area. However, the applications are limited as the mechanism of ASS is not clear. In this work, the effects of sample matrix, experimental factors, etc. on stacking were systematically studied. A new reasonable hypothesis about the mechanism of ASS was proved to be an 'acetonitrile caused quick large volume stacking combined with NaCl induced pseudo isotachophoresis' procedure, and several experiments were carried out to verify the conclusion.