Chromatography Forum

I'm trying to evaluate the mechanisms by which amino acids are detected using IEX with PED at high pH.

Oxidation of the amine group of all amino acids at high pH with applied PED waveform leads me to believe that either a hydrazine or azo (double bond linkage of N's) cmpd forms.

The 3rd option is NH2 --> NO2

Any thoughts on this? I cannot seem to find a reference detailing the mechanism in the literature. If anyone has a reference, could you please email me at chemometrics@gmail.com or post here?

Thanks!

Chembot,

I'm fairly certain the process is significantly more complex than a simple oxidation to one of the functional groups mentioned. Typically such systems are multi-electron processes involving several intermediates. Dennis Johnson was one of the pioneers in this area and I would suggest that you delve into what he has written on the topic. A good starting point, although not on amino acids per se: "A study of ethylamine at a gold rotating ring-disk electrode using pulsed electrochemical detection at the ring", David A. Dobberpuhl & Dennis C. Johnson, Electroanalysis, Volume 8, Issue 8-9, pages 726-31. This article will supply you with a lot of other relevant references on the topic.