Solid-state ion sensors with a liquid junction-free polymer membrane-basedreference electrode for blood analysis

A set of ion-selective membranes for the measurement of clinically relevant electrolytes, i.e., K+, Na+, Ca2+, H+ and Cl-, and a solvent-processible p olyurethane (PU)-based reference membrane were cast on metal electrodes pat terned on small ceramic plates, and on silicon-based sensors. Since the liq uid junction-free PU membrane-based reference electrode provides a constant potentiometric signal for an extended period of time, accurate determinati on of blood electrolytes could be made without using a separate reference f low. The PU membrane-based reference electrodes not only improve the mass p roducibility of miniaturized solid-state ion sensors but also simplify the configuration of flow cell. cartridges without compromising their analytica l performance. (C) 2000 Elsevier Science S.A. All rights reserved.