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

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 Cu 2+ 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 Cu 2+ . 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 Cu 2+ has also been successfully fabricated to discriminate amino acid enantiomers and even the enantiomeric excess (ee) of mixtures at the designed concentration ranges.