An electronic circular dichroism spectroscopy method for the quantification of L- and D-amino acids in enantiomeric mixtures.

Ruiwen Ding,Yufen Zhao,Jianxi Ying

doi:10.1098/rsos.201963

Abstract

Rapid quantitative analysis of single chiral amino acid (aa) was achieved using circular dichroism (CD) with data analysis by standard calibration curve. The absolute concentrations of D- and L-aas in enantiomeric mixtures were determined by CD and achiral liquid chromatography (LC) method. It is worth noting that CD and LC were used independently, not online LC/CD in this study. The errors of the experimental results were less than 10%. The method is also applicable to the quantification of non-aa chiral molecules, such as chiral nucleoside and chiral quinine. With this study, we provide a new method for the chiral quantitative analysis of enantiomeric aas mixtures.

Highlights

Amino acids are the most important chiral biomolecules that act as the building blocks of peptides in living organisms [1]
To test the possibility of using circular dichroism (CD) spectroscopy to quantify the concentration of single aa, a series of known concentrations of 19 natural L-amino acids (L-aa) were measured by CD, and construction of calibration curves involves five points of the corresponding pure L-aa
The results showed that linear correlation between CD signal θ and L-aa concentration c was found in a certain concentration range

Summary

Introduction

Amino acids are the most important chiral biomolecules that act as the building blocks of peptides ( proteins) in living organisms [1]. L-amino acids (L-aa) are selected as the predominant conformation materials to form the peptides by the natural selection, D-amino acids (D-aa) can been found in organisms and show important effects on biological processes [2–4]. Analytical methods for chiral amino acid (aa) are of unquestionable and general importance. Liquid chromatography (LC), mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy are usually employed for the analysis of chiral molecules [5–7]. The application of MS in chiral analysis is based on royalsocietypublishing.org/journal/rsos R. Soc. Open Sci. 8: 201963 mass-resolve adducts generated by the additives and the analytes [14–17]. Chiral reagents are used for 2 chiral analysis of NMR [18,19]

Methods

Results

Conclusion