A new reference method for the determination of the oxygen content of blood.

To be able to determine the slight differences between the theoretical and the actual O2-binding capacity of human haemoglobin, a highly accurate method has been developed for measuring the O2 content of blood samples. It is an adaptation of an established O2 determination in organic microanalysis. The bound O2 of the blood is set free by conversion of HbO2 to Hi, and the O2 stripped from the blood is converted to CO by contact with granular carbon at 1120 degrees C. The CO is then converted to CO2 using CuO at 300 degrees C and the CO2 titrated in a solution of BaCl2, using NaOH of known strength. The measuring system was checked by analysis of 36 samples of air, yielding an O2 content of 20.93 +/- 0.06%. The coefficient of variation calculated from 62 duplicate determinations of samples of human blood was 0.65%.