Efficiency Enhancement in the Capillary Electrophoretic Separation of Aromatic Acids with Organo-Silica Nanoparticles as Pseudo-Stationary Phase

Abstract

Nanoparticles modified with aminopropyl group were prepared by a single-step electrospray process and used as a pseudo-stationary phase for the separation of anions, (e.g., organic acids in capillary electrophoresis). The nanoparticles form a uniform suspension which is stable in a buffer without adding other stabilizer. The amino containing nanoparticles have significant impact on the electro-osmotic flow (EOF) of the system, which, in turn, affects the overall separation of other analytes in this system. For example, five organic acids, which were not all separable in zone electrophoresis, were fully resolved in the presence of the nanoparticles in a wide range of pH. Various experimental parameters that are related to the electrophoresis including EOF, pH, organic modifier, voltage, concentration of the running buffer and concentration of the nanoparticles have been investigated. The repeatability of the migration time and peak area in this system are better than 5% for both inter- and intra-day evaluation.