ABSTRACT
In an amperometric enzyme electrode the function of the enzyme is to generate an electroactive species in a stoichiometric relationship with its substrate or target analyte. The determination of serum cholinesterase activity plays an important role in anesthesiology. The MB isoenzyme of serum creatine kinase was determined by T. Fonong, using an immunoinhibition amperometric technique. Enzymes have mostly been immobilized in membranes or gels, but direct coupling to the transducer can also be achieved as exemplified in modified electrodes. The technique was very convenient for oxidases, and other types of enzymes were immobilized on the surface of collagen films. Glucose oxidase immobilization could also be achieved on graphite disks using adipic dihydrazide to cross-link the enzyme. Enzymes have been chemically immobilized on nylon nets through lysine spacers and glutaraldehyde after treatment with dimethylsulfate and 2,4,6-trinitrobenzenesulfonic acid. In amperometry electrochemical processes are generally complex and may be considered a succession of electron transfers and chemical events.
