ABSTRACT
This chapter discusses metal cation-responsive glass electrodes to the exclusion of the well-known H+-responsive glass electrodes. In glasses, as in liquids, there is short-range but no long-range order. For silicate glasses, Zachariasen's model is generally adopted, which consists of Si04 tetrahedral units with each corner connected through common oxygens. When glass is in contact with a fused salt or ionic solution, cation exchange takes place, which may most easily be detected radiochemically. The time response of cation-responsive glass electrodes can be very slow, probably because of slow hydration effects, as was found in the studies of Savage and Isard. It is always advisable to try several samples of a given electrode type and, even better, to try several manufacturer's products. Although when this is done, steady values are reached in a series of solutions. The principal applications of cation-responsive glass electrodes are in water analysis and in clinical biochemistry.
