use of an ion selective electrode and method for the determination of carbon dioxide in body fluids

摘要

The present invention concerns an ion-selective electrode for interferent-free determination of carbon dioxide and other analytes in aqueous samples. The invention also relates to a membrane structure and a method for analysis of body fluids containing analytes and interferents. The electrode according to the present invention comprises an internal reference electrode (1, 2), a liquid-phase ion-selective membrane (3) and a discriminating membrane (4) comprising a hydrophilic membrane having a medium pore size of less than 0.1 mu m. The liquid-phase ion-selective membrane is placed in intimate contact with the discriminating membrane, which preferably comprises a membrane made from cellulose fibers, regenerated cellulose fibers or fibers of cellulose derivatives.