Diethanolamine in caustic treating solutions

Chromatography Forum: GC Archives: Diethanolamine in caustic treating solutions
Top of pagePrevious messageNext messageBottom of pageLink to this message  By Les on Thursday, March 4, 2004 - 03:39 pm:

I was looking for a column capable of getting DEA from the caustic. These caustics contain dirt, NH3, and several sulfur species. I would need to use FID. Please don't suggest a very expensive column, I won't buy it. I have a variety of old/used columns: wax, methylsiloxane, plots, and a few odd fellows...anyone with a prefered phase that could handle the caustic and not fall apart in a few runs? Would you go split? Temps for inlet and oven. Amount of injection. I'm not sure of the exact amount of DEA.
I recently boiled the caustic on a hot plate and returned to volume with water. Place on Antek N analyzer and came up with @8% DEA. This value seemed a little too high and I assumed this was caused by N salts. But the conc may be that high.
Any suggestions would be greatly appreciated.


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Friday, March 5, 2004 - 09:23 am:

Assuming you are discussing capillary columns and not packed columns, even so, the presence of salts will make your analysis difficult if not impossible to be accurate.

I would think that LC or even TLC might be a better solution, but that was not your question, was it?

a middle polarity phase would be best, and a thicker film rather than a thinner one.

Good luck


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Ian on Sunday, March 7, 2004 - 02:29 pm:

Les - try this (I must admit I haven't tried it, but the chemistry sounds OK). Add to your mixture acetone. A carbonyl and a primary amine forms a Schiff base (exothermic reaction). Then neutralise your caustic with dilute HCl and inject. Your liner should obviously be cleaned very often.
Another option: Convert the caustic with CO2 to the carbonate - the amine might also react, but the amine can probably be liberated again with acetone. Good luck - Ian.


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