GLUTATHIONE AMPEROMETRIC ENZYME MICROSENSOR

Glutathione micro-enzyme sensors were developed based on the immobiliz ation of glutathione oxidase at the tip of a 25 mum Pt wire sealed in glass. An inner membrane constructed from cellulose acetate (CA) was d eposited onto the tip of the Pt microelectrode prior to enzyme immobil ization with glutaraldehyde. The final outer diameter of the microelec trodes is approximately 30 mum. The analytical characteristics of the microelectrodes, including calibration curves, apparent K(M)', pH resp onse curves, stability and selectivity over enzymatic interferences we re determined. The response was linear in the concentration range 1.0 x 10(-5) M - 1.9 x 10(4) M glutathione, reaching 95% steady-state curr ent in 15-20 seconds. The microelectrodes were useful for more than tw o months.