Summary
Based on our detailed analysis of the influence of both dissolved H2 and pH as well as ORP, it should be clear that measuring the reduction potential of hydrogen water using an ORP meter is not the appropriate way to determine the level of dissolved hydrogen gas.
While dissolved H2 is responsible for the negative ORP value, based on the negative values we can only conclude that some amount of dissolved H2 is present in the water. Systemic fluctuations of the ORP meter, combined with the large impact that even small changes in pH have on ORP, will always determine the ORP measurement and do not allow us to use the height of the reading to determine how much H2 is present.
While there are laboratory devices that measure dissolved H2, they cost between $10.000 and $100.000 or more.
In contrast, the cheap portable dissolved hydrogen meters we discussed are based on ORP technology and only measure redox potential, not dissolved H2.
While consumers are conditioned to trust measurements produced by digital electronic devices, they are not always the best choice.
Notes
- Diluted concentrations measured in “ppm” correspond to mg/L
- The hydrogen ion is referred to as H+, instead of its aqueous form, H3O+ (hydronium ion)
- The term “concentration” is used when referring to ion/solute density instead of “activity”
- For simplicity, the redox couple 2H+/H2 is referred to here as H+/H2
- Nernst calculations and graphs carried out with MS Excel 2013 / V
Excerpt from the book by Randy Sharpe: “The relationship between dissolved H2, pH and redox potential”
