SUBFEMTOMOLE DETECTION OF CATECHOLAMINE WITH INTERDIGITATED ARRAY CARBON MICROELECTRODES IN HPLC

An IDA carbon microelectrode for HPLC was fabricated by photolithographic techniques from the carbon film of pyrolyzed 3,4,9,10-perylenetetracarboxylic dianhydride on thermally oxidized silicon wafers. The IDA electrode consisted of 300 pairs, the finger widths and gaps were 5 mu m, and each finger was 2 mm long. The electrode in a small-volume thin-layer cell incorporated in a microbore HPLC system achieved a low detection limit for dopamine due to current enhancement by redox cycling and low background noise at the carbon IDA microelectrode. The detection Limit of 0.5 fmol of dopamine can be realized because of the low noise level and high current density.