An All Solid-State Electrochemical Electrolyte Analyzer

Ion-selective electrodes have been applied to analysis of blood electrolytes with some success. However, currently available ion-selective electrode systems tend to be elaborate and expensive. We describe a clinical electrolyte analyzer in which inexpensive ion-selective electrodes are used. The electrodes are in the configuration of thin wires and are all solid in construction. They may be dipped directly into undiluted 250-µl samples of serum or plasma, are nondestructive of the sample, and may be used with an expanded-scale pH meter, although a more sensitive electrometer is preferred. The complete electrolyte analyzer consists of an electrode holder, into which the electrodes are plugged, and a solid-state digital electrometer that displays units of electrolyte concentration. A discussion of the thermodynamics essential to the construction of reversible electrodes is also presented, as well as the results of a clinical study in which it is shown that data from a flame photometer and the electrochemical analyzer compare favorably.