carbonate analysis

[Marion]

Hi all,

I am dealing with a very alkaline solution (pH=12.5) and I need to determine carbonates in that solution. The only equipment that I have at this moment in the lab are a TOC analyzer (which I think that cannot be used with such an alkaline media) and an HPLC (AGILENT 1100) that is supposed to have a conductivity detector. I have never used any of them…

Is there any possibility of using a “simpleâ€

[Peter Apps]

Hi Marion

Have you considered acidifying the solution and measuring the volume of carbon dioxide that evolves ?. Very often the simple methods are the best.

Peter

[Marion]

Hi Peter thanks for your answer!

Yes, we have considered acidifying the solution and producing CO2(g). However, the only option that we have here to “measureâ€

[DR]

Or you could contrive some sort of sealed system and capture the evolved gas in an inverted graduated cylinder, measure the volume and apply the perfect gas law related equations (you'll need to know temp and barimetric pressure).

[gcguy]

Don't really want to ask the obvious but....

Are you trying to determine the levels of different carbonates? If you are only interested in the total carbonate content why not try a simple acid base titration?

GCguy