Effect of zwitterionic surfactants on the separation of proteins by capillary electrophoresis

The effect of zwitterionic surfactants on capillary electrophoretic separation of proteins was investigated using an uncoated silica capillary column and different buffers containing zwitterionic surfactants. The effects of N-alkyl-N,N-dimethyl ammonio-1-propane-sulfonates on the electrophoretic mobility of three different proteins, namely albumin, lysozyme and myoglobin, were examined. The addition of N-alkyl-N,N-dimethylammonio-1-propane sulfonate in phosphate saline buffer is important in minimizing protein-capillary wall interactions, and facilitated an efficient electrophoretic mobility of myoglobin and lysozyme. The separation efficiency of proteins also depends on the injection pressure for the control of migration time and the peak sharpness. The electrophoretic conditions were applied to evaluate the separation of lysozyme, myoglobin and albumin. The zwitterion surfactants can form a dynamic coating on the capillary surface, thereby reducing the number of adsorption sites to which proteins may adsorb.