EVALUATION OF MICROELECTRODE ARRAYS FOR AMPEROMETRIC DETECTION BY SCANNING ELECTROCHEMICAL MICROSCOPY

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 participati on of each array element in the heterogeneous redox reaction can be ch ecked with the help of scanning electrochemical microscopy (SECM). Bec ause the active electrode area is recessed compared to the insulating cover layer of the sensor, a loss in sensitivity is found on such arra ys compared to an electrode array of the same geometry which is in pla ne with its insulating surrounding. Consequences for the application o f such electrode arrays as the basis OF sensors ill hand-held devices for in-field testing are discussed.