How can I check the sodium content of food?

What is an easy (i.e., home project) way to measure sodium in food? 


For example, the nutritional label of a tahini brand that I often consume shows very little sodium (around 10mg/100g). I suspect the sodium content is much higher.


What is the chemical way to measure the salt content?




Sodium is a difficult ion to estimate at home. 


Since *most* sodium salts are water-soluble, [colorimetric](https://pubs.acs.org/doi/abs/10.1021/i560116a029?src=recsys) or [spectroscopic](https://doi.org/10.3168/jds.2014-9055) 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](https://en.wikipedia.org/wiki/Argentometry#Mohr_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](https://pdfs.semanticscholar.org/90e7/ac0f90bf50c0cbf0811242dc59c436008e2a.pdf)
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.
2. There are sodium ion meters, you can get them for ~300$.
3. 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.


**Conclusions**


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.




---


**References**


[1] J. Am. Chem. Soc. 1931, 53, 9, 3288-3291 [DOI: 10.1021/ja01360a011](https://pubs.acs.org/doi/abs/10.1021/ja01360a011)


 6