This microelectrode, which, in principle, resembles the Clark polyethylene membrane electrode, may be used for the measurement of O2 tension in biological fluids. It is unaffected by the presence of fats, proteins, or hydrated ions in the external fluid and possesses the following characteristics: external diameter, 0.75 mm, O2 tension to current relationship linear over a range of Po2 0—702 mm Hg; accuracy ±0.5% at 150 mm Hg; stability over several hours ±0.5%; response time to 99% at 37 C is 2 min; temperature/current relationship, linear or curvilinear; temperature equilibrium, 1 min; movement/current relationship, logarithmic; approximate maximum effect of movement, 4%. The application of membrane electrodes to the measurement of O2 within tissues is discussed. The electrodes may also be used to measure the resistance of tissues to dissolved O2 transport. The concept of “relative available oxygen” is introduced.
Submitted on December 9, 1960
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