# What is the standard electrode potential of human blood?

Healthy humans have a pH of around 7.4 (slightly basic.) But if you hooked up the blood as a battery how much electric voltage would one generate, what is the standard electrode potential?

This seems to me like it should be important for stuff such as transporting ions across the cell membrane.

If I think about it this question basically comes down to if things like iron tend to dissolve $\ce{Fe -> Fe^{2+} + 2e^-}$ (SEP of 0.44) or precipitate $\ce{Fe^{2+} + 2e^-->Fe}$ in human blood.

Because of important chemicals like haemoglobin I think the SEP should be around 0.44 but differs depending upon whether cells are absorbing oxygen from it or recharging it with oxygen. Maybe this would even vary depending on whether heavy exercise is happening.

• Not related to the question: the blood pH of 7.4 is not basic: that's the neutral pH. The neutral pH varies according several factors: 7.0 is the neutral pH of pure water, and even so at a given temperature only (25 C). At 0 C, for instance, the pH of pure water is higher than that 7.4 for the blood. Thus, have in mind that a blood with pH of 7.3 is acidic, not basic.
– user24284
Commented Jun 19, 2017 at 4:28
• @GerardoFurtado Right. $K_{eq} = e^{\frac{-\delta G}{RT}}$ so the neutral equilibrium and resultingly pH varies with temperature. I just never connected that to acid stuff. Commented Jun 19, 2017 at 4:35
• Sorry, I'm just a bit confused. I thought the electrode potential depended on the oxidation and reduction potentials of the two dissimilar metals, not on the electrolytic medium. Am I missing something? Commented Jun 22, 2017 at 15:53
• @anonymous2 In a Galvanic cell one electrode will dissolve and another electrode will gain a coating. If an electrode is stuck in the human body the electrode would start to gain some kind of coating or start to dissolve. In response, the body would start to deal with the excess of new ions or deal with the loss of ions and maintain homeostasis for a bit until the person starts getting sick. Commented Jun 22, 2017 at 20:30
• I don't think @anonymous2 is confused, I think the question makes no sense. You can't just stick an electrode in the blood, the electrode has to be made of something. Your explanation skirts around that problem: "In a Galvanic cell one electrode will dissolve and another electrode will gain a coating" - what's the electrode that is dissolving and what's the electrode that is gaining a coating? Commented Jun 23, 2017 at 21:15