Chromatography Forum

Hi,

Can any one suggest to me any referrence for ammonium analysis using HPLC? Sample will be supernatant from cell extract. Thanks

Louise

Here is method for ammonia and other simple amines. You need ELSD detector to detect:
http://www.sielc.com/compound_005.html
Contact me if you have questions.

Vlad

Cation chromatography with conductivity detection will be the easiest way to analyse ammonium ions.
Ammonium does not absorb UV. Therefore UV detection will be difficult.
With the respective column and a conductivity detector it will be possible to run such sample even on a standard HPLC system.

A suitable cation-exchange column with suppressed conductivity detection can do the job.

The two links below provide some information of this approach.

http://www1.dionex.com/en-us/columns_ac ... 34323.html

http://www1.dionex.com/en-us/columns_ac ... s2722.html

The easiest approach will be as mentioned in earlier responses ion chromatography with conductivity detection. Depending on the concentration levels in which other small ions may be present, you will have to make an informed decision on which cation exchange column to use. Supressed conductivity detection will give you better minimum detection levels and more importantly, more options on your eluent concentration, thus allowing the use of cation exchange columns of higher capacity. In case of resolution problems with other closer-eluting ions such as sodium, it will also enable the use of gradient elution.