Studies of Migration Time Reproducibility of Capillary Electrophoretic Protein Separations

Abstract

Studies of the migration time reproducibility of trypsinogen were performed using a capillary electrophoresis system designed for high resolution protein separations, where analyte adsorption and electroosmotic flow were minimized through the use of poly-(acrylamide)-derivatized capillaries coated with 3-(dimethyldodecylarnmonio)-propanesulfonate, a zwitterionic surfactant The results of this investigation suggested that oxidation/reduction-induced pH drifts occurring at the electrodes had a significant impact upon protein migration. Acceptable migration time reproducibility (<2% RSD for a series of nine injections) was found to be dependent upon buffer replenishment at both electrodes prior to each injection. These results indicate that instruments which can provide pre-injection buffer replenishment may be necessary for the qualitative or quantitative analysis of proteins using poly-(acrylamide) coated capillaries.