Table 1.
Solutions
| 1.5% CO2/10 mM HCO3− |
5% CO2/33 mM HCO3− |
10% CO2/66 mM HCO3− |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| HEPES | HEPES | HEPES | ||||||||
| Component | ND96 | 1 | 5 | 25 | 1 | 5 | 25 | 1 | 5 | 25 |
| Sol. 1 | Sol. 2 | Sol. 3 | Sol. 4 | Sol. 5 | Sol. 6 | Sol. 7 | Sol. 8 | Sol. 9 | Sol. 10 | |
| NaCl, mM* | 96 | 88 | 86 | 76 | 65 | 63 | 53 | 32 | 30 | 20 |
| KCl, mM | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 |
| MgCl2, mM | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| CaCl2, mM | 1.8 | 1.8 | 1.8 | 1.8 | 1.8 | 1.8 | 1.8 | 1.8 | 1.8 | 1.8 |
| HEPES, mM* | 5 | 1 | 5 | 25 | 1 | 5 | 25 | 1 | 5 | 25 |
| HCO3−, mM | 0 | 10 | 10 | 10 | 33 | 33 | 33 | 66 | 66 | 66 |
| pH | 7.5 | 7.5 | 7.5 | 7.5 | 7.5 | 7.5 | 7.5 | 7.5 | 7.5 | 7.5 |
| Osmolality, mosmol/kgH2O | ≅195 | ≅195 | ≅195 | ≅195 | ≅195 | ≅195 | ≅195 | ≅195 | ≅195 | ≅195 |
*
We titrated HEPES free acid (pK 7.5) to pH 7.5 with NaOH (so that, theoretically, we have incremented H-HEPES, HEPES−, and Na+ concentrations by equal amounts) and then secondarily adjusted [NaCl], as indicated in this table, to achieve a final osmolality of ∼195 mosmol/kgH2O.