SANDWICH ENZYME MEMBRANES FOR AMPEROMETRIC MULTI-BIOSENSOR APPLICATIONS - IMPROVEMENT OF LINEARITY AND REDUCTION OF CHEMICAL CROSS-TALK

Amperometric thick-film multisensors for the simultaneous determinatio n of glucose and sucrose are described. The enzymes glucose oxidase an d invertase are immobilized in a matrix made from aqueous poly(vinylac etate) dispersions. Sandwich membranes are obtained by printing two or more membrane layers on top of each other. This technique effects the elimination of interferences, such as ascorbic acid, and enables the enlargement of the linear ranges of determination for glucose and sucr ose. In addition, catalase, either co-immobilized with glucose oxidase or used in a separate cover membrane, can be used to improve the line arity and to eliminate chemical cross-talk between electrodes of multi biosensors.