Immobilization of uricase to gas diffusion carbon felt by electropolymerization of aniline and its application as an enzyme reactor for uric acid sensor

Electropolymerizations of aniline and pyrrole solutions containing uricase at a neutral pH was performed to immobilize the enzyme on the surface of the gas diffusion carbon felt, and a selective uric acid sensor was fabricated by combining immobilized enzyme carbon felt and an oxygen electrode with oxygen gas permeable membrane. This carbon felt has a desirable feature for uricase sensing because an extremely efficient supply of oxygen for the enzymatic reaction can be realized due to its porosity permitting a transfer of oxygen. The current response time required from when sample is added until when current reaches the steady-state value is < 5 min. The calibration graph of uric acid showed a linear line in concentration range from 1 x 10(-5) to 4 x 10(-4) M with a detection limit of 4 x 10(-6) M. (C) 1997 Elsevier Science B.V.