This work presents the integration of an electrochemical detector in a photoablated polymer microdevice with electroosmotic driven how. The structure of the device features a separation capillary with two side arms forming the injection capillaries, an electrical decoupler and an electrochemical detector. The decoupler is composed of a microhole or microhole array perpendicular to the separation microchannel. The system allows the electrical high voltage connection between the inlet of the capillary and the decoupler; the remaining end of the separation capillary being almost free of electric field, facilitating an electrochemical detection at the end of the microchannel. Separation parameters have been varied comprising the electrophoretic potential, the time of the injection and the buffer composition. Separation of model phenolic compounds is shown here as a demonstration of the system.