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Home water tests for lead have an accuracy of about 15 ppb. If I first do a gentle/slow boil for one hour (hot plate under a glass beaker of water) to reduce 2000 mL to 20 mL, will I then effectively be able to detect 0.15 ppb?

My goal is really just 1 ppb.

My main concern now is that any lead might adhere to the glass (though I think these home tests have a reagent which helps dissolve lead in case of this) so, if this is truly a problem, is there a better beaker material or boiling method to use?

Of course, if improvement were this easy, I would expect the test kits to already be recommending it, so I am probably making some mistake. Please explain it.

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  • $\begingroup$ I mean the test for non VOC salts is to literally burn the filter paper at 600C so I don't think you are going wrong concentrating the water. I do think your method should work $\endgroup$ Commented Sep 17, 2022 at 19:12
  • $\begingroup$ You might have another approach, which involves using household acid (lemon juice) to enhance recovery. The relevant publication is here. The article is: Challenges of Detecting Lead in Drinking Water Using at-Home Test Kits Rebecca Kriss, Kelsey J. Pieper, Jeffrey Parks, and Marc A. Edwards Environmental Science & Technology 2021 55 (3), 1964-1972, DOI: 10.1021/acs.est.0c07614 $\endgroup$ Commented Sep 17, 2022 at 19:39
  • $\begingroup$ Of course I do not know the origin of the water to be analyzed. But reducing a water volume from $2000$ mL to $20$ ml is not so easy as it looks, because boiling tap water does usually produce a deposit of calcium carbonate, which may adsorb the lead ions $\ce{Pb^{2+}}$ during its precipitation. $\endgroup$
    – Maurice
    Commented Sep 17, 2022 at 19:42
  • $\begingroup$ @ToddMinehardt The lemon juice is basically the "reagent which helps dissolve lead" that I mentioned, so yes, of course that additionally should be optimized, but my question here is focused instead on getting rid of molecules that are not lead. $\endgroup$
    – bobuhito
    Commented Sep 18, 2022 at 18:18
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    $\begingroup$ @bobuhito. If the solution is totally evaporated, a powder will be obtained containing all $\ce{CaCO3}$ plus a rather tiny amount of lead. Now redissolving this powder in the minimum amount of diluted nitric acid (or citric acid) can give you a solution containing calcium and lead, where the test for lead can be carried out. $\endgroup$
    – Maurice
    Commented Sep 18, 2022 at 19:48

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