A capillary electrophoresis conductometric detector based on measurement of the conductivity of a plastic hydrophilic strip

A new approach to the solution of the problem of interference of the intense electric field encountered in CE with electrochemical detection is described. The conductometric detector is designed so that the conductivity is determined of the solution emerging from the capillary outlet and trapped in a hydrophilic plastic strip which connects the capillary end that is not directly immersed in solution, with the solution in the outlet electrophoretic vessel. One conductometric electrode contacting the hydrophilic strip is placed at the side of the capillary and is thus sufficiently shielded from the electric field and the other is far from the capillary end in the outlet vessel. Basic performance characteristics of the detector are determined and compared with those obtained using a standard UV detector The detector was tested for determination of sodium and potassium ions in natural mineral waters.