You may be wondering, “What level of dissolved H2 is needed to produce a negative ORP”?
To determine the amount of H2 needed to produce even a “moderate” level of negative ORP, we can use the Nernst equation. This allows us to predict the ORP at different H2 concentrations while keeping the pH at 7 (the answer may surprise you!).
In Figure 6 you can see that at a pH of 7, an H2 concentration of only 1 × 10-5 mg/l (0,00001 mg/l), or one hundred-thousandth of a milligram per liter (orders of magnitude below the level known as considered therapeutic) is necessary to produce a negative ORP of -260 mV.
Note that such a low dissolved H2 value produces this negative redox potential value “on paper” using only the Nernst equation when no other redox couples in the water are taken into account.
If a water sample actually contains such an extremely low level of dissolved H2, other oxidizing redox couples also present in the water (e.g. an oxygen species) would surpass the negative redox potential of the H+/H2 redox couple and the water would become positive instead Show ORP reading. However, this shows how only a very low level of H2 is capable of producing a negative ORP.
As we will see, a negative ORP value actually says very little about how much H2 is dissolved in the water.
To create a slightly negative ORP, only a tiny amount of dissolved hydrogen is required. At pH 7, 1×10-13 mg/L (0,1 trillionth of 1 mg/L) will produce an ORP of -24 millivolts.
Excerpt from Randy Sharpe’s book: “The Relationship Between Dissolved H2, pH and Redox Potential”
