Table 1.
Empirical equilibrium concentrations of main small ions (in mOsm/L H2O) in human blood plasma (assumed total protein equivalent: − 12.2 mEq/L) and interstitial fluid (assumed total protein equivalent: − 4.3 mEq/L) from Guyton and Hall17 and the associated equilibrium concentrations of ions in the interstitial fluid along with the theoretical values of the Gibbs–Donnan factor calculated using the presented method (Eq. (16)).
| Ion | Empirical equilibrium concentrations: plasma | Empirical equilibrium concentrations: interstitial fluid | Estimated equilibrium concentrations: interstitial fluid | Estimated Gibbs–Donnan factor |
|---|---|---|---|---|
| Na+ | 142.0 | 139.0 | 138.3 | 0.97 |
| K+ | 4.2 | 4.0 | 4.1 | 0.97 |
| Ca2+ | 1.3 | 1.2 | 1.2 | 0.95 |
| Mg2+ | 0.8 | 0.7 | 0.8 | 0.95 |
| Cl− | 108.0 | 108.0 | 110.9 | 1.03 |
| HCO3− | 24.0 | 28.3 | 24.7 | 1.03 |
| Lactate− | 1.2 | 1.2 | 1.2 | 1.03 |
| SO42− | 0.5 | 0.5 | 0.5 | 1.06 |
| HPO42− | 2.0 | 2.0 | 2.1 | 1.06 |