Oxygen sensitivity of a multichannel antimony microelectrode for tissue surface oxygen pressure measurements.

The measuring properties of antimony electrodes were improved by the introduction of highly purified crystallographically oriented monocrystalline antimony (COMA). COMA electrodes are sensitive to pH and pO2. For measurements of either pH, pO2, or both, the pH and the pO2 sensitivities must be known and the components of the composite electrode signal must be separable. The oxygen sensitivity of COMA electrodes in vivo have been shown to be higher than in vitro in the pO2 range below 10 kPa. The present study was performed in an animal model to investigate the oxygen sensitivity and to further evaluate the tissue pO2 measuring properties of a miniaturized six channel COMA microelectrode. The results show that the COMA microelectrode has negligible drift, a response time of less than 5 s and high sensitivity and reproducibility for tissue pO2 measurements when the pH part of the electrode signal is eliminated. The oxygen sensitivity found (8.5 +/- 0.4 (mV/pO2) (mean +/- SEM)), is described by a direct linear function in the oxygen tension range studied. It is concluded that tissue pO2 can be calculated after elimination of the pH part of the electrode signal. A multichannel COMA microelectrode possess characteristics suitable for in vivo oxygen measurements and is therefore an interesting complement to traditional tissue oxygen sensors.