Simplified amperometric detector for capillary electrophoresis

The design of a new amperometric detector for capillary electrophoresis is described. By employing the electrophoretic counter electrode as a polarized pseudo-reference electrode with an appropriate electronic circuitry it was possible to carry out the detection with a single electrode, the working electrode which is mounted in the wall jet arrangement. It is demonstrated that this approach delivers reliable results which are comparable to those obtained with conventional three-electrode potentiostat arrangements. Detection of catecholamines, ascorbic acid, carbohydrates, and heavy metals using different working electrodes is demonstrated, these being examples of possible applications. The simplicity and robustness of the detector cell make it well suited for its use in a field-portable instrument.