I want to quantify the hydrolysis of tris(2-chloroethyl)amine using GC-MS (OV-101 column). I use hydrochloride of the base (pKa 4,6). I must not inject water samples. I tried salting the water sample out by NaCl followed by extraction into butan-1-ol or dichloromethane. Subsequently in the chromatogram I can see reduced amount of the original base but there are no peaks from bis(2-chloroethyl)-2hydroxyethylamine, bis(2-hydroxyethyl)-2-chloroethylamine and triethanolamine. I suggest that the hydrolysis products were polar enough to not cross into the nonpolar phase. Any suggestions how to put the desirable peaks on the map?
I would try to increase the pH of the solution above the pKa of the amines and then retry the extraction with salting-out effect only if necessary as you have already tried. You can do both using basic salts like bicarbonate/carbonate concentrated solutions.
Hi Florian, thanks for your answer. Actually, I also tried to perform the experiment in a buffered polar environment (pH 11,5). Then salting out, extraction and injection into GC. Only a small peak of the original base was present in the chromatogram.
Quite surprising given the high octanol/water partition coefficient of HN3... A concentration or a detection problem maybe...
I think the HN-3 was hydrolysed and that is why I could see just a small peak (it was for 2 hours in the buffer). But the peaks from decomposing products are missing. Salting out + dichloromethane as the extracting solvent is actually very effective for HN-3 itself. Maybe not for the decomposing products but i would suggest at least a small portion of them should undergo the extraction...
hmmm I think I understand the issue now, you want to identify/quantify the decomposition products but you can not extract them from water. Yep, it's quite surprising you observe nothing at all, above all in butanol I would have expected a small fraction at least. Why not LC-MS analysis instead of GC? I had good results in identifying/quantifying trace amounts of amines in aqueous phases using LC-MS...
I´m sorry probably I did not express my issue exactly - you are right, I want to quantify the products of HN-3 decomposition in water. Unfortunately we do not possess a LC-MS in our lab.
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