Evaluation of Microelectrode Arrays for Amperometric Detection by Scanning Electrochemical Microscopy

Abstract

Ultramicroelectrode arrays have been manufactured by a combination of screen printing and laser ablation with different sizes of the active electrode areas and different interelectrode spacings. The participation of each array element in the heterogeneous redox reaction can be checked with the help of scanning electrochemical microscopy (SECM). Because the active electrode area is recessed compared to the insulating cover layer of the sensor, a loss in sensitivity is found on such arrays compared to an electrode array of the same geometry which is in plane with its insulating surrounding. Consequences for the application of such electrode arrays as the basis of sensors in hand-held devices for in-field testing are discussed.