Quaternary Ammonium Compounds

[MJ]

Hi,

I am chasing a HPLC method that can separate Quaternary Ammonium Compounds that are present in our cleaning solutions. Does anyone know a method or where I can find a method?

Cheers

[XL]

MJ,

Cationic surfactants and related quats are challenging to analyze. Acclaim Surfactant column (Dionex) is a silica based HPLC column specially designed for separating different types of surfactants, including anionics, cationics, nonionics and amphoterics. You can find an article about this column (American Laboratory 2005) in the following link: http://littledomain.com/james/files/pit ... dionex.pdf

Since then more work on surfactant analysis have been done. This link leads to some latest data including separation and detection of cationic surfactants you are interested in. Please pay attention to Figures 1, 2, 6-9.
http://www.dionex.com/en-us/webdocs/709 ... 230-01.pdf

I believe Acclaim Surfactant column is most likely suitable for your application. Please feel free to contact me if you have further questions.

Thanks,

[MJ]

Thanks for the articles, they were helpful. I cant order a new column at the moment so have to develop the method on a RP C18 column. I dont have a DAD so those articles gave me a good starting point for a wavelength of 220 or 225nm to start at. I will also run the samples on the UV-Vis spectro incase there are any other wavelength of interest.

I will do a few runs with a methanol/water gradient runs to see what mobile phase ratio to use and then optimise further.

If any one has already developed a method on a RP C18 column I would appreciate the run parameters.

cheers

MJ

[XL]

MJ,

There are many methods published using conventional RP silica columns when you do an internet search. I tried the same thing at the beginning when I was working on cationic surfactant analysis four years back. When using regualr silica RP columns, you need to keep pH low (trying to keep silanols protonated) and use high concentration of salt (such as perchlorate trying to mask the anionic silanol sites). Even so, it is challenging to get symmetrical peaks for quats. If you only analyze quats with UV chromophre, a RP column might be bearable. If you have to analyze the ones without chromphore, RI might be your only choice. Then you need to use isocratic method and will suffer low sensitivity. I am sure you will know many tricks once you start doing so.