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Re: Mystery water

> Date: Sun, 19 Oct 1997 21:56:18 -0500
> From: Ed Hengel <hengel at computer_net>
> Subject: Curiouser and Curiouser;  Hmmm.
>
> There seems to be a lot going on in the water we drink.  After reading
stuff deleted

> (recalibrated Pinpoint PH meter, LaMotte alkalinity and Co2 test kits)
>
>             PH    Kh    Co2
> Tap            5.75    3.8    215ppm
> Boiled            6.8    3.8    30ppm
> RO            4.5    .784    210ppm
> Tap 2 day light        7.4    3.8    10ppm
> Tap 2 day dark    (underway)
>

> If any of the above appears to corroborate anyone's notion as to what is
> causing the aberrant co2 readings, I'd sure like to hear it, especially
> the RO co2 #.  And if anyone would like to suggest an experiment that
> might clear things up a bit, I game.
>
> Ed

I think someone already suggested you get a profesional analysis done.
But since you have a pH meter, you might consider doing a potentiometric
titration of your water sample(s).
Make up separate solutions of a strong alkalie and strong acid to use as
titrants. Monitor the pH of the solution while adding small aliquots of the
titrant.  By analyzing the shape of the titration curve, pH vs. amount
added, you can make an estimate of the pKa of the weak acid that is
giving you the false CO2 reading. Consult a textbook of analytical
chemistry for details.  Of course, if you have more than one contaminant,
such as a mixture of phosphate and organic acid, you might not learn much.
My apologies to those of you interested in plants.
--
Curtis Hoganson        Dept. of Chemistry, Michigan State University
East Lansing, MI 48824                517-355-9715 ext 260