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- Posts: 2
- Joined: Mon Oct 06, 2014 1:07 pm
i recently started a new project that requires the analysis of (single) amino acid substrates and its reaction products.
a typical sample will for example contain serine and ethanol amine or in another sample lysine, caprolactam and amino-caprolactam.
i have been working with isocratic solvent compositions in order to be able to use the RID detector for analysis....
I have tried seperating these compounds using a varierty of different columns including, an agilent C18 Zorbax Eclipse Plus as well as different HILIC columns...additionally i have tried eluiting compounds with various different solvent compositions including 100 H2O to 85/15 Acn-H2O mixtures with Ammonium acetate buffes...the best results sofar I obtained using a 85/15 AcN-H2O-0.1 M NH4Ac mixture adjusted to ph = 8...however the chromatograms are still not suitable for analysis because many of the peaks, i.e. lysine and amino-aprolactam have identical retention times.
im not sure where my mistake is but i feel like it should be releatively simple to sepearte these compounds due to there vastly different polarity (amino acid vs. reaction products)...does anyone have any advice on where i could be going wrong?
thanks alot in advance
best regards
david