How do u test for heavy metals?

Question

i'm doing an experiment where i want to prove that pH affects the solubility of heavy metals in water....how can i test for this?? i was thinking of actually putting the metals in the water (each test having a different pH)...but how do would i test if the metals have dissolved or reacted?

Answer 1

I recommend precipitating out the metal as it dissolves in the water.  The more metal compound precipitate you get (you can mass it, it'll be solid), the more metal dissolved.  Which precipitate compound you try for depends on the individual metal, so if you add more details I can add tips on getting good precipitates for specific metals.

Edit:  If you choose a precipitate that's not soluble in water, it'll come out as dust that you can collect in a filter.  The precipitate will be very physically different from the metal.  It might be white and powdery.  It definitely won't look at all like a metal.  If you need to, you can lower the temperature to decrease solubility (rock salt works to make ice colder).  

Edit:  Oh, by the way, here's a website that teaches you how to test conductivity of water.  Keep in mind that any non-neutral water has ions in it.  So you can only do this conductivity test at the pH of 7.  But it is pretty handy for detecting ions.  Website:  http://scifun.chem.wisc.edu/homeexpts/Co...