Nitrate And Bicarbonate Selective Chemfets

The development of durable anion selective CHEMFET micro sensors is described. Selectivity in these sensors is either obtained from differences in hydration energy of the anions (the Hofmeister series, giving nitrate selectivity) or by introduction of a new class of uranyl salophene ionophores (bicarbonate selectivity). The durability of the nitrate sensor was enhanced by using polysiloxane membranes in which cationic tetraalkylammonium sites were covalently bound to the membrane matrix.