A method for conducting capillary zone electrophoresis in which a lubricating detergent is added to help prevent sample buildup on the inner walls of the capillary. In a preferred embodiment the lubricating detergent is sodium dodecylsulfate (SDS) in a concentration of about 3 mM added to a protein sample before the sample is introduced into one end of a capillary. The SDS may be added to the buffer, instead of the sample, before electrophoresis.