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ammonium salts

Posted: Tue Mar 04, 2014 8:57 am
by EdytaK
I am looking for an analytical procedure to determine the concentration of some quaternary ammonium salts in a solution with GC-MS. I was adviced to search for that in the NIST databse. Unfortunately I don't have access to it. Can anyone with that access tell me if there are any spectra or analytical procedures available for the salt didecyldimethylammonium chloride or any other similar in structure substance? I would be grateful for help

Re: ammonium salts

Posted: Tue Mar 04, 2014 9:58 am
by dblux_
... I was adviced to search for that in the NIST databse. Unfortunately I don't have access to it. Can anyone with that access tell me if there are any spectra or analytical procedures available for the salt didecyldimethylammonium chloride or any other similar in structure substance? I would be grateful for help
Start with this:

http://www.sisweb.com/software/ms/nists ... earch+NIST

Re: ammonium salts

Posted: Tue Mar 04, 2014 1:29 pm
by EdytaK
Start with this:

http://www.sisweb.com/software/ms/nists ... earch+NIST[/quote]

Thank you. I am interested in CAS #3282733-Didodecyldimethylammonium bromide. Is there a chance that anyone could check the information about the GC performance for that formula? I would be extremely grateful

Re: ammonium salts

Posted: Tue Mar 04, 2014 3:39 pm
by Peter Apps
I suspect that this molecule is not amenable to GC - a quick google of its name and GC has it being used only as a stationary phase to characterise its properties. What attempts have you made to find a method ?

Peter

Re: ammonium salts

Posted: Tue Mar 04, 2014 7:59 pm
by dhdh
I am looking for an analytical procedure to determine the concentration of some quaternary ammonium salts in a solution with GC-MS. I was adviced to search for that in the NIST databse. Unfortunately I don't have access to it. Can anyone with that access tell me if there are any spectra or analytical procedures available for the salt didecyldimethylammonium chloride or any other similar in structure substance? I would be grateful for help

Many of the "Quats" will break down in the hot injection port to give multiple peaks, mainly tertiary amines and chloroalkanes. So you can expect dimethyl decyl amine, methyl didecyl amine, and chlorodecane. I have never seen any quaternary ammonium compound elute intact on GC.

Benzalkonium chloride (one of the best-known quats) has a related structure and is a good example to use as a search term. The spectra of its breakdown products are shown in the Pfleger-Maurer-Weber database (sorry, but it's not available free on the web). I've verified these breakdown peaks with some reference standards (not just by library search or retention index).

For years I've been looking for ways to quantitate quats, but don't have access to LC-MS. There is some kind of titration method which is relatively simple, if your solution doesn't contain many interferences. Hope that helps (although probably not what you wanted to hear). Dan

Re: ammonium salts

Posted: Wed Mar 05, 2014 3:08 pm
by dblux_
...
Can anyone with that access tell me if there are any spectra or analytical procedures available for the salt didecyldimethylammonium chloride or any other similar in structure substance? I would be grateful for help
Edyta, if still interested open the link for MSD spectrum of your compound (in fact bromide not chloride) from NIST library:

http://www.whb.dnx.pl/NIST%20MS%20Search%20hardcopy.pdf

Re: ammonium salts

Posted: Mon Mar 10, 2014 9:45 am
by EdytaK
Thank you all for help. Before I asked for a piece of advice here I was told that GC is not used for quats because of their negligible volatility, so I was expecting what you in fact told me. I just needed this presumption to be confirmed by specialists. Greetings, Edyta

Re: ammonium salts

Posted: Mon Mar 10, 2014 10:14 am
by Peter Apps
Hi Edyta

If you just wanted to know whether quaternary ammonium compounds can be analysed by GC, why all the smokescreen about your not having the NIST library ?.

Just ask what you want to know, you will get better answers, quicker.

Peter