Wall-less stationary pH boundary for stacking proteins on a glass microchip

This work reports a new electrophoretic stacking protocol based on the formation of a stationary pH boundary to concentrate and analyze proteins on a glass microchip. The feasibility of continuously loading proteins from a continuously flowing sample to increase the amount of analyte injected prior to separation and detection was demonstrated. An increase in protein concentration of about 800-1000 fold was achieved in approximately 5 min of stacking, and the subsequent separation and detection of three different protein bands namely BSA, β-lactoglobulin and as r-phycoerthrin were achieved within 3 min.