Blood O2 content measurements using the oxygen electrode

A method is described for determining the oxygen content in whole blood with the membrane-covered oxygen electrode that requires less time and skill than the Van Slyke-Neill technique. A blood sample (0.05 ml) is mixed with a large volume of dilute (0.2% w/v) potassium ferricyanide solution in equilibrium with ambient air and the oxygen tension of the mixture is measured at a known temperature. The whole-blood oxygen content is obtained by subtracting the calculated O2 content of the ferricyanide solution from that of the blood-ferricyanide mixture. The method is based on the assumption that the Bunsen O2 solubility coefficient of the ferricyanide solution, with or without the added blood sample, is equal to the solubility coefficient of water. Data have been presented to validate this assumption. Whole-blood O2 contents measured simultaneously with the oxygen electrode and the Van Slyke-Neill technique were found to be in close agreement. flood-gas determination Submitted on January 11, 1965