Conductivity detection in capillary electrophoresis--a powerful tool in ion analysis

Conductivity detection in CE has recently become available in a commercial CE instrument. The new conductivity cell is based on an end-capillary concept. The conductivity sensor and the detection end of the fused-silica capillary are permanently encapsulated in two individually modified coupling connectors (ConTip, ConCap [both from Orion Research, Boston, MA, U.S.A.]). This open-architecture cell permits interchangeability of sensors and capillaries, while maintaining a precisely defined detection volume between those two components when inserted into the detector cell block. The detector's performance is evaluated for sensitivity, linearity, and reproducibility using low-mobility electrolytes. Electropherograms comprising a variety of ionic class separations including inorganic and organic anions, organic surfactants, alkali metals, alkaline earths, transition metals, and organic amines are shown along with separations of actual samples.