Importance of medium solutes in polarographic measurement of low oxygen consumption rates

Abstract

1. 1. Solutes in biological media change both the solubility and the activity coefficient of oxygen. 2. 2. When 0.5% glucose was added to a buffered electrolyte medium, the Clark electrode oxygen consumption (blank), as measured by the rate of fall in pO 2, increased precipitously and was not reproducible thereafter. 3. 3. With 0.02% glucose present the electrode was relatively stable for 2 days, but the standard deviation of the blank was 4–6 times greater than without it. 4. 4. The magnitude and variability of the electrode blank must be determined in the medium to be employed to preclude significant error in polarographic measurement of low rates of oxygen consumption.