I would like to use LC/MS to screen for the present of unknown degradation products of triethanolamine. I have no literature as what the triethanolamine will be converted to in the water maxtrix which contain calcium chloride and sodium chloride at pH5. It was observed by LC/MS that triethanolamine disappeared after 2 hrs in the maxtrix. I am not sure what triethanolamine has been converted to. It can be polar or non polar compound. Is it possible to screen for unknown by LC/MS if the polarity of the compound is unknown? If possible, please advice on the protocol.

I intend to try the following:
1) Run a sample blank and sample with triethanolamine through RP column (C18). Scan from 50-2000 by MS. Compare the two spectrum and observe for any abnormal peak. Hope this will cover any nonpolar compound that might form.

2) Repeat the above with HILIC column. Hope this will cover the polar compound.

This will be like searching for a needle in the hay stack. Its the only options I can think of.
It will be difficult to work out the structure but I hope to confirm the present of triethanolamine by pattern matching.

Anyone with similar experience, Please advice.

Thanks in advance

That sounds okay to me. I don't know what would be the degradation products, but keep in mind that if it's too nonpolar, it might not ionize. Identifying unknowns with LC/MS is always tough, even with MS/MS.

Triethanolamine doesn't readily degrade under these conditions. Are you sure you are not just losing it via adsorption or do you have something else present that can react with triethanolamine?

Dear Lily,

triethanolamine is sometimes used to mask acidic silanol groups with RP phases. As Chris wrote, adsorbtion is very likely to happen.
I suggest to use at first no column at all and narrow the scan width. FIA runs are very fast so you can scan different m/z ranges within a few runs (but matrix can be a problem).
Columns from the YMC Pro familiy (C4, C8, C18 and Hydropshere) are more unaffected from bases than other RP materials I have tested. Maybe Chris, Uwe Neue or others can give you further advice.

Thank you for the reply

Chris and Andreas

With my matrix, it is not possible to run without a column. However, I do not think that the lost of triethanolamine was due to adsorption on the column. I can achieved 60% recovery of triethanolamine spiked in matrix left to stand for 30mins. After 1hr of standing, no triethanolamine was detected. The results were reprodubile for 10 runs.

The matrix contains sodium dichloroisocyanurate, calcium chloride and sodium chloride. I believe that triethanolamine might be converted into something else, eg calcium complex.

Thank you for the advice. I will continue to work on it. I will post the results if I have any findings.

Best regards
Lily

Lily

With the additional info this all makes a lot more sense. Dichloroisocyanurate will most certainly degrade any amine fairly rapidly. Dichloroisocyanurate degrades to form hypochlorite in solution which can both oxidize portions of the molecule, generally forming organic acids as well as adding chlorine to the nitrogen forming chlorinated amines in the process. Degradation products should include glycolic acid, possibly oxalic acid and various chloramines degradation products. Chloramines are typically analyzed by reverse phase and the organic acids formed can also be handled by reverse phase. Probably, though, it would be advisable to work with a mobile phase that is near neutral to get maximum retention of the chloramines (they are relatively weak bases and so pH seven should be sufficient to keep them in their neutral form) but you need to be at low pH with with 100% aqueous eluent to get retention the organic acids. Alternatively, as you suggest you could also try HILIC but I would suggest testing their analytical system with model compounds in that case. Finally, it might be worthwhile considering a WAX column for the organic acids and a WCX column for the chloramines.

Chris

Thank you for your advice. I have screened the sample with Primesep 100 column, which is mix-mode chromatograhy. I did not observe any of the degradation products. The mobile phase is 0.1% TFA : ACN (95:5). Next, I will try the reverse phase and will keep you update. Meanwhile, do you know of any literature reference which I can read about the reaction of dichloroisocyanurate with triethanolamine. I have search through all the organic chemistry textbook in the library and couldn't find any info.

Regards
Lily

According to our data you may retain and separate some of the compounds mentioned by Chris using (ZIC™)-HILIC.

Organic acids like propionic, formic, oxalic, citric acid are retained and resolved at neutral pH using 70 % acetonitrile/30% buffer.

We have not tested triethanolamine, but it seems reasonable that it also will be retained at these conditions. I would not be surprised if the chloramines are as well.

Lily,

I'm afraid I can't point you to any specific references on triethanolamine-dichloroisocyanurate reactions and reaction products. My knowledge in this regard stems from experience gained both at Dionex and at Clorox early in my career. I think you'll find some references about chlorination of amines if you take a look at more widely studied systems such as reactions of hypochlorite with ammonia and reactions of hypochlorite with triethanolamine.

Lily,

One other point to note is that there's really not much point in using a column containing weak cation-exchange sites for the analysis of chloramines. In the first place, chloramines are very weak bases (I found one reference stating that monochloramine's pKa is 14) so you most likely won't be able to get any retention via cation-exchange, especially weak cation-exchange. Also, as far as I can tell its more stable at near neutral pH and since its quite reactive your best hope is to operate at a pH of maximum stability. But frankly I'm a bit doubtful that you can accomplish this separation of chloramines without significant decomposition, given their reactivity.

Chris

Chris,

Can you suggest a typical acidic and neurtal pH mobile phase composition which I can use for screening on C18 column?

Lily

Environment Canada has a report on inorganic chloramines which refers to the existence of an HPLC method (I can e-mail you a copy if you're interested). I couldn't find any details except some vague description of the method which implied it used a neutral pH on a reversed phase column. The following link gets you to the site but it looks like you need to e-mail them directly to get the specific methodology (http://www.ec.gc.ca/substances/ese/eng/esehome.cfm ). For the organic acids, I guess your best shot is still trifluoroacetic acid in an aqueous eluent.

Chris

With your valuable advice, I am able to proceed with my research. Will post findings later.

Lily