Patent ID: 8795499

Claim:
A method for separating a complex, the method comprising: (1) introducing in a capillary, between a leading buffer zone and a trailing buffer zone, wherein neither the leading buffer nor the trailing buffer comprises an ion selected from a 2-(N-morpholino)ethane sulfonate ion and a glutamate ion: (a) a blood-derived sample suspected of containing an analyte, (b) a labeled analyte analog, and (c) one or more mobility-changing complex forming substances (CFS); (2) contacting the analyte, the labeled analyte analog, and the one or more mobility-changing CFSs, wherein a first complex comprising the labeled analyte analog and at least one of the one or more mobility-changing CFSs and a second complex comprising the analyte and at least one of the one or more mobility-changing CFSs are formed; and (3) separating the first complex from the labeled analyte analog not part of said first complex and coexisting substances in the blood-derived sample by performing isotachophoresis in the presence of a 2-(N-morpholino)ethane sulfonate ion and/or a glutamate ion between the leading buffer zone and the trailing buffer zone.