Experimental design to investigate factors affecting capillary zone electrophoresis

Abstract

An experimental design approach is described to evaluate the main electrophoretic parameters involved in neuropeptide separation by capillary zone electrophoresis coupled to ultraviolet detection. Response surface methodology based on a three-level, three-variable Box-Behnken design was used for optimization with respect to buffer pH, buffer concentration, and applied voltage. The optimum conditions of these variables were predicated by using a second-order polynomial model fitted to the results obtained by applying the Box-Behnken design. The methodology identifies the principal experimental factors, which have significant effects in the separation. The optimum conditions were 100 mM phosphate buffer pH 2.5 as the background electrolyte and an applied voltage of 6 kV. Verification experiments were performed under optimal conditions, which yielded 98% of the predicated efficiency.