Carbon paste-based ion-selective dual function microelectrodes for SECM measurements

A description of the preparation and characterization of 25 μm diameter modified carbon paste-based Cu2+ ion-selective electrodes are reported. The electrodes have a linear potential response within the 10−3 to 10−6 M range and a 16 s response time. A substantial benefit of this new type of ion-selective microelectrode (ISME) is the capability to use them as a dual function tip, in either the amperometric or the potentiometric mode of scanning electrochemical microscopy (SECM). The applications reported also support the usefulness of copper ion-selective carbon paste microelectrodes in SECM potentiometric imaging.