Sodium- and potassium-sensitive glass electrodes for biological use.

Continuous, accurate recording in circulating fluids from a sodium and a potassium electrode is described. The Na electrode is capable of discriminating Delta[Na(+)] of less than 1 meq/lit. in 140 meq/lit., and the K electrode is capable of discriminating Delta[K(+)] of less than 1 meq/lit. in the range of 1 to 10 meq/lit. with good reproducibility. The electrodes may be used singly or in pairs with a common reference calomel electrode for simultaneous monitoring of A [Na(+) 1 and Delta[K(+)] in mixed solutions. Problems of streaming potential dependent on flow rate and electrode shape, as well as transient K(+) response by the Na electrode, are discussed.