Chromatography Forum

Hello,
i have a basic question about IC:
My supervisor wants me to identify unknown ions in certain liquids. we expect some materials so we chose:
boric acid, ammonium pentaborate, ammonium hydroxide, phosphoric acid and ethylene glycol.
we first want to run them in IC to identify their typical peaks and then run them as our own standards for the sample liquids.
in my first test, i didnt get any valuable plot for boric acid (just a peak for fluoride and chloride).
is it possible to do it this way or what is the mistake im doing?
thanks in advance

"The devil is in the details"

What kind of instrument, what column, what mobile phase, and how are you detecting?

If you are using "suppressed conductivity", then borate is a problem because of the high pKa. One work around is to complex the borate with sugars, as in this paper:
http://www.rsc.org/ej/AN/1998/a803924k.pdf

ethylene glycol is non-ionic, and so is not a good candidate for IC at all.

thanks for the answer.
im using dionex equipment: AS50 and CD25 with a cation column. we're not using a suppressor.
as eluent were using 12mM/L NaOH.
at the time I was writing this thread I ran a second test and got better results I think.
if it would help I could post the results.

AS50 and CD25 with a cation column.

As I said before "the devil is in the details"; which cation column?

More to the point, borate, fluoride, pentaborate, chloride, and phosphate are all anions. The only cation you mentioned is ammonium.

Before investing too much effort in this, you might want to do a search on the web sites of Dionex and Metrohm (two suppliers of IC equipment) and see what they have to offer for what you're trying to do. If nothing else, it will give you a feel for some of the possible pitfalls.