A PCO2 surface electrode working on the principle of electrical conductivity.

A PCO2 electrode working on the principle of electrical conductivity is described. The calibration curve can be linearized according to the formula G = Go + b square root PCO2. This linearity has been tested in the PCO2 range of 0.93-9.33 kPa (7--70 Torr). For the experiments electrodes are used which have conductivity values of about 50 nS and drifts of maximally 5%/h at a PCO2 of 5.33 kPa (40 Torr). The response time (T90) is about 20 s. The temperature sensitivity is 2.4 nS/1 K between 298 K-310 K. The standard error of the measurements is sigma = 0.33 nS. With these electrodes tissue PCO2 can be measured on the surface of various organs.