Diffusion coefficients of oxygen and hemoglobin measured by facilitated oxygen diffusion through hemoglobin solutions

Diffusion coefficients of oxygen (D-O2) and hemoglobin (D-Hb) were obtained from measuring the oxygen flux through thin layers of hemoglobin solutions at 20 degrees C. The liquid layers were supported by a membrane and not soaked in any filter material. Oxygen fluxes were measured from the changes in oxygen partial pressure in the gas phases at both sides of the layer. A mathematical treatment is presented for correct evaluation of the measurements. Measurements were done for bovine and for human hemoglobin. Hemoglobin concentrations (C-Hb) were between 11 and 42 g/dl, which covers the concentrations in the erythrocyte. Both D-O1 and D-Hb could be fitted to the empirical equation D = D-0(1 - C-Hb/C-1)10(-CHb/C2). The following parameters were obtained: D-0 = 1.80 x 10(-9) m(2)/s, C, = 100 g/dl, C-2 = 119 g/dl, for oxygen and D-0 = 7.00 x 10(-11) m(2)/s, C-1 = 46 g/dl, C-2 = 128 g/dl, for hemoglobin. No difference between the diffusion coefficients of bovine or human hemoglobin was found. The diffusion coefficients of hemoglobin were higher than most values reported in the literature, probably because in this study the mobility of hemoglobin was not hindered by surrounding filter material.