# Chiral Chromatographic Analysis of Amino Acids with Pre-column Derivatization by o-Phthalaldehyde: Improving the Determination of Enantiomers Using Ion-Pair Reagents

## TL;DR

This paper introduces a method to improve the separation of amino acid enantiomers using ion-pair reagents in chromatography.

## Contribution

The novel contribution is optimizing ion-pair reagents and mobile phase composition to enhance chiral amino acid analysis.

## Key findings

- Adding ion-pair reagents improves the resolution of diastereomeric isoindole peaks.
- Increasing ionic strength reduces analysis time.
- Optimizing mobile phase composition is a useful approach for chiral amino acid analysis.

## Abstract

The development of effective and accessible methods for the chiral
analysis of amino acids is an important scientific and practical necessity. One
of the most common and convenient techniques is the chromatographic
determination of individual enantiomers of amino acids with preliminary
conversion of enantiomers into diastereomers, which can then be separated on
conventional achiral columns. We have shown that by adding ion-pair reagents to
the eluent and varying their structure, one can regulate the efficiency of a
chiral amino acid analysis based on the chromatographic determination and
resolution of the diastereomeric isoindoles obtained upon pre-column
derivatization of amino acids by o-phthalaldehyde in the presence of
N-acetyl-L-cysteine. The use of ion-pair reagents allows one to achieve a
better resolution of diastereomeric isoindole peaks, while the analysis time
can be reduced by increasing the ionic strength. Hence, adding ionpair reagents
and optimizing the mobile phase composition are useful approaches in the
engineering of an amino acid chiral analysis, along with the synthesis of new
chiral SH compounds and the choice of stationary phases.