EFFECT OF MULTIPLE ELECTROLYTE BUFFERS ON PEAK SYMMETRY, RESOLUTION, AND SENSITIVITY IN CAPILLARY ELECTROPHORESIS

The use of multiple electrolyte buffers in capillary electrophoresis was investigated from theoretical and experimental points of view. A series of model substituted aromatic carboxylic acids was used to investigate the effect of different combinations of buffer co-anions on individual analyte peak symmetry. A theoretical model with computer simulations was used to aid in the interpretation of the observed peak dispersion phenomena. The cumulative data demonstrate that it is possible to simultaneously optimize peak symmetry for a mixture of different analytes with widely varying mobilities by judicious choice of the buffer co-ions, The value of this approach for controlling peak symmetry was demonstrated in terms of both optimization of resolution and sensitivity for mixtures involving analytes with a broad range of mobilities and samples composed of widely varying concentrations of the individual species. In addition, the utility of this technique for improving sensitivity for low-level weakly UV-absorbing impurities was demonstrated, Potential problems encountered in using multiple electrolyte buffers were discovered and their effects interpreted with the aid of the computer simulations.