End-column conductivity detector for capillary zone electrophoresis

摘要

An end-column conductivity detector is described. A sensing electrode is placed in the outlet end of a capillary that has a hole in its side wall through which electrolyte moves past the sensing electrode into a reservoir that contains the ground electrode. This structure is simple to construct, has almost no dead volume, and minimizes electrolyte contact with adhesives used to mount the sensing electrode. The end- column conductivity detector is operated in conjunction with a commercial capillary zone electrophoresis system that has a capillary cartridge and a UV absorption detector. This design thus permits sequential measurement of the absorption and conductivity characteristics of separated analyte zones. When a species can be detected by both conductivity and UV absorption, then the absorption coefficient can be determined from the relation between the conductivity signal and the concentration of the species.