Sciencemadness Discussion Board

Chemical tests for heavy metals

reactofurnace - 24-6-2019 at 20:37

Guys i'm working on testing various water samples.

Are there viable tests for: (preferably in low concentrations but once it has a distinctive qualitative result)
1) Mercury(I & II)
2) Lead
3) Cadmium
4) Manganese
5) Chromium

If possible using lab reagents.


eBay ?

Sulaiman - 24-6-2019 at 20:48

https://www.ebay.co.uk/itm/Heavy-Metals-Water-Test-Strips-Co...

https://www.ebay.co.uk/itm/Heavy-Metals-Water-Test-Kit-Test-...

unionised - 25-6-2019 at 10:34

How much money do you have?
How good a detection limit do you need?

Bedlasky - 25-6-2019 at 12:20

Mercury(I) salts have white insoluble chloride. If you add ammonia to mercury(I) chloride precipitate turns to black do to formation of elementar mercury.

Mercury(II) salts have orange iodide solube in excess of iodide.

Cadmium(II) have yellow-orange sulfide.

Manganese(II) is oxidized by sodium hypochlorite in slightly basic media to purple permanganate

Chromium(III) is oxidized by sodium hypochlorite or hydrogen peroxide in basic media to yellow chromate

But this is only simple tests.

[Edited on 25-6-2019 by Bedlasky]

Metacelsus - 25-6-2019 at 12:54

I'd expect the limit of detection of those tests to be well above the level of dangerous toxicity. Mercury has a drinking water limit of 2 ppb, which is certainly not detectable by the methods of qualitative inorganic analysis.

I would suggest ICP-AES. It's not exactly amateur friendly, but this kind of thing is best left to professionals.