2 of 2 added tiny bit to the conclusion

Sodium is a difficult ion to estimate at home.

Since most sodium salts are water-soluble, colorimetric or spectroscopic methods are often employed, both of which I assume are not within arms' reach.

Some alternatives:

  1. Speaking of sodium estimation in foodstuff, it is usually determined by Mohr's method which involves the precipitation titration of $\ce{Cl-}$ ions. This is done under the assumption that sodium is mainly present as sodium chloride. Additionally, it will also register $\ce{Cl-}$ from other chlorides, and hence may give an elevated reading. You might be able to do this at home. Here is a page to help you with the process.

It is done in the presence of chromate ion ($\ce{CrO4^2-}$), and $\ce{Ag+}$ ions are added gradually. This precipitation happens initially:

$$\ce{Ag+ + Cl- <=> AgCl(s)}$$

When the solution runs out of $\ce{Cl-}$ ions, precipitation of the red-brown $\ce{Ag2CrO4}$ begins:

$$\ce{Ag+ + CrO4^2- <=> Ag2CrO4(s)}$$

This signals the end point.

  1. There are sodium ion meters, you can get them for ~300$.

  2. There is a volumetric estimation[1] for sodium directly, but it is not expedient to do it. It is based on the precipitation of sodium zinc uranyl acetate.


IMO it is difficult to do this as a home project, as it will require stuff that is not usually found at home to do it precisely.


[1] J. Am. Chem. Soc. 1931, 53, 9, 3288-3291 DOI: 10.1021/ja01360a011