Enantiomer Elution Order
Reversal of the Enantiomer Elution Order Based
on the Chemical Structure of the Chiral Selector
The position claiming that any reversal in EEO with changing
the chemical structure of the polysaccharide-based CSP is rather common and therefore of little interest, is in our
opinion incorrect. The fact is that such reversal is still hard
to rationalize and predict. Therefore, EEO must be established
by systematical screening of combinations of CSP
and mobile phase conditions and reporting such results is
of great interest to analysts. This can be a significant step
forward in understanding of chiral recognition mechanisms
with polysaccharide-based CSPs. Of especial interest
are cases of reversal of EEO caused by fine structural
or chemical modifications of chiral selectors. For instance,
the reversal of EEO for arylpropionic acid derivatives on
polysaccharide phenylcarbamate-based chiral selectors has
been analyzed function of the position of substituents on
the phenyl moiety [42], of changing one polymer backbone
with other (cellulose vs. amylose) while keeping the pendant
groups the same [42], etc., In the present study, several
examples of EEO reversal based on the chemical structure
of the chiral selector were observed (Table 1).