Sodium dodecyl sulfate polyacrylamide gel electrophoresis for direct quantitation of protein adsorption.

A simple method, sodium dodecyl sulfate polyacrylamide gel electrophoresis coupled with direct protein adsorption analysis (SDS-PAGE/DPA), is presented here for the quantitation of adsorption-caused protein loss. No complicated steps and expensive equipment are involved, and this method is capable of measuring proteins adsorbed on sample vials at extremely low concentrations (in pg/µl). We used this method to characterize the effects of concentration, time, and volume on adsorption. We also applied this method to discover differential sample loss in protein mixtures and its utility in developing preventive strategies of adsorption.