One‐step hydrothermal preparation of chiral carbon quantum dots and enantioselective sensing of glutamine enantiomeric isomers

Abstract

AbstractA novel method for chiral identification of glutamine enantiomers based on chiral carbon quantum dots (cCQDs) fluorescent probes. cCQDs were prepared using a one‐step hydrothermal method with L‐tryptophan as the carbon source and chiral source, producing spherical nanoparticles exhibiting a blue colour luminescence. The fluorescence intensity (F) of cCQDs was enhanced or quenched following the addition of chiral enantiomeric glutamine (L/D‐Gln), and therefore cCQDs, as a fluorescence probe, could be used for enantioselective sensing of the L/D‐Gln. The fluorescence enhancement value (∆FE) exhibited good linearity with L‐Gln concentration in the range 0.23–10.00 mM, and the limit of detection was 0.14 mM. The fluorescence quenching value (∆FQ) showed a good linear relationship with D‐Gln concentration in the range 0.29–10.00 mM, and the detection limit was 0.18 mM. The mechanism of fluorescence enhancement/quenching was explored by molecular modelling and the type of quenching. The method was applied to the determination of L‐Gln content in real samples, and the recovery rate was satisfactory. This study provided a novel approach for the synthesis of cCQDs and the recognition of amino acid enantiomers.