Capillary electrophoresis enzyme immunoassay

A method for performing an assay, said method comprising:

• (a) conducting a heterogeneous competitive reaction in a vessel among an immobilized reactant, an analyte, and a competitor, wherein the competitor comprises a biorecognition portion and a second reactant portion;
• (b) introducing an aliquot of the competitor which is unbound in step (a) into a channel containing an electrophoresis medium and a first reactant;
• (c) imposing an electrical potential along the length of the channel to cause, the second reactant portion of the competitor and the first reactant to form or deplete a detectable product within the channel;
• and
• (d) detecting the detectable product.

An analytical device comprising a capillary zone electrophoresis channel, said channel comprising:

• a free solution electrophoretic medium,
• a first reactant in said electrophoretic medium that will react in said channel with a second reactant portion of a competitor to form or deplete a detectable product wherein the competitor further comprises a biorecognition portion;
• and
• said analytical device further comprising electrical power means for applying a field across the ends of said channel to cause said first reactant and said second reactant portion of said competitor to migrate and react.