Investigation of chloride sensitive ISFETs with different membrane compositions suitable for medical applications

Cl(-)-ion sensitive ISFETs with photocured polyurethane-based polymer membranes with six different ionophores (ETH 9033, ETH 9009, MnTPPCl, organotin compounds and traditional ion-exchanger TDMACl) have been studied in pure NaCl solutions and in background solutions containing anions in concentrations normally found in a whole blood and serum. PVC or silicon resin were used to form the membranes in cases when it was not possible to use the photocurable polymer composition. Experimental results on determination of chloride ions in serum samples are presented. Performed tests showed that all chloride-selective ionophores commercially proposed up to now, both neutral and charged carriers, do not provide better selectivity and stability of chloride ion sensors for clinical application than the traditional anionic ion-exchanger TDMACl.