Micromethod for dynamic determination of O2 dissociation curves using a PO2 electrode.

A nonspectrophotometric method is described for measurement of the O2 dissociation curve and O2 capacity of a 50-microliter sample of fluid. PO2 is recorded by a microprocessor as the sample is oxygenated and then deoxygenated by exposure to isocapnic gas mixtures across a gas-permeable membrane. The time course of deoxygenation and the O2 conductance of the membrane are used in calculating the O2 capacity of the sample and the dissociation curve. The method is sensitive and is best suited to samples of low O2 capacity and affinity. Measurements on buffer-diluted human blood agree with standard values.