Three-Minute Enantioselective Amino Acid Analysis by Ultra-High-Performance Liquid Chromatography Drift Tube Ion...

Area of Science:

• Analytical Chemistry
• Separation Science
• Mass Spectrometry

Background:

• Accurate enantiomeric separation of amino acids is crucial for peptide and protein analysis.
• Existing methods often lack the speed or selectivity required for complex biological samples.
• 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) derivatization is a common approach for amino acid analysis.

Purpose of the Study:

• To develop a rapid and highly selective method for amino acid enantiomer separation.
• To enhance separation capabilities by combining liquid chromatography (LC) with ion mobility-mass spectrometry (IM-MS).
• To validate the developed LC-IM-MS method for quantitative analysis in peptide samples.

Main Methods:

• Fast enantioselective liquid chromatography (LC) using a chiral core-shell particle tandem column.
• Drift tube ion mobility-mass spectrometry (IM-MS) as an orthogonal separation technique.
• Density functional theory (DFT) calculations to understand ion mobility separation mechanisms.

Main Results:

• Baseline separation of AQC-derivatized proteinogenic amino acid enantiomers and some isomers in under 3 minutes.
• LC-IM-MS successfully resolved threonine isomers (threonine, allo-threonine, homoserine) and confirmed their structures.
• The method demonstrated accuracy and precision suitable for bioanalytical applications, with successful application to peptide samples.

Conclusions:

• The integrated LC-IM-MS approach provides a powerful tool for rapid and selective amino acid enantiomer analysis.
• Ion mobility separation offers an effective complementary dimension to LC, particularly for resolving challenging isomers.
• The validated method is applicable to the quantitative analysis of amino acid enantiomers in complex biological and synthetic peptides.