Assessment of a commercial pH electrode used with blood.

With the recent development of ion selective electrodes, potentiometry has entered a new era of usefulness ranging from pollution control to the investigation of single cells. Routine use of these sensors in the clinical environment is severely restricted due to errors associated with the reference electrode. Due to the Nernstian response of the potentiometric sensors the entire reference and ion selective electrodes are housed within a thermostatically controlled heater assembly. A clinically based thermostatically controlled combined ion selective/reference electrode system is discussed and a simple algorithm is presented to correct for the additional liquid junction potential encountered when monitoring biological solutions.