Chiral discrimination of amino acid enantiomers based on different interactions with Cu2+

- A versatile fluorescent probe for chiral discrimination of amino acid enantiomers has been successfully fabricated.
- It is the first time to realize the chiral discrimination using achiral host platform.
- The designed hybrid FL probe exhibit excellent chiral discrimination properties, not only for basic and acidic amino acid enantiomers but also for ee value determination, with a wide range of application.
- The proposed sensor for chiral discrimination of amino acid enantiomers is highly rapid, excellent simple and sensitive, also a visual process.

Chiral discrimination of amino acid enantomers could give us a better understanding of the fundamental processes in organisms since enantiomers may have opposite biological effects. However, most of the reported chiral discrimination methods were based on different interaction between the chiral host platform and amino acid enantiomers, the chiral discrimination probes using achiral host platform have not been explored yet. Herein we reported the development of an easy, rapid and sensitive discrimination methodology of amino acid enantiomers using achiral materials, which relied on the different coordination between Cu2+ ions and amino acid enantiomers. These coordinations could result in different pH values of samples containing the same amount of l- or d-amino acid enantiomers and Cu2+. By introduction of pH-responsive fluorophore 5(6)-Carboxyfluorescein (CF), above pH variation could be easily detected through fluorescence (FL) spectrometter, which could be utilized to determine the variety of amino acid enantiomers (including basic and acidic amino acids). Moreover, a more convenient achiral polyacrylamide (PAM) hydrogel containing CF and Cu2+ has also been successfully fabricated to discriminate amino acid enantiomers and even the enantiomeric excess (ee) of mixtures at the designed concentration ranges.