By Mary on Thursday, October 30, 2003 - 02:09 am:
Has anybody an idea how to separate different isomers of sugar adducts to secondary amines? I know from 1H-NMR that I have got five different isomers of a glucose-adduct to an amine function--
By Zelechonok on Thursday, October 30, 2003 - 07:27 pm:
Allsep Technologies is offering a mixed mode column with hydrophobic and ion-exchange properties.
In the application database you can find an example of separation of isomers of amino sugars and their impurities. The column is Primesep 100. Conditions are MeCN/H2O/H2SO4 – 8/92/0.03, See chromatogram:
http://allsep.com/makeChr.php?chr=Chr_012
H2SO4 allows to go to low UV
If you need MS compatible conditions 0.1% TFA can be used instead of H2SO4 .
If some isomers are co-eluted you can play with amount of acetonitrile from 0 to up to 80%.
You can also use another column Primesep 200. This column has slightly weaker ion-exchange properties but offers higher selectivity toward structural isomers. With Primesep 200 ammonium acetate 5-50 mMol can be used to get MS compatible conditions. The selectivity of the column changes drastically with different mobile phase.