(Digital Presentation) One-Step Hydrothermal Preparation of Chiral Carbon Quantum Dots and Its Chiral Recognition of Glutamine Enantiomers

Abstract: A novel method for chiral recognition of glutamine enantiomers using fluorescence intensity changes of chiral carbon quantum dots(CCQDs) is proposed. CCQDs was prepared by one-step hydrothermal method with L-tryptophan as carbon source and chiral source, which are spherical nanoparticles exhibiting blue color luminescence for fluorescence probe to recognize glutamine enantiomeric isomers[1] . Fluorescence intensity(∆Fe )enhanced by addition of L-glutamine to CCQDs solution and ∆Fe was well linear with L-glutamine concentration in the range 0.01-5.0 mM and the limit of detection was 0.22 mM. Fluorescence quenching(∆Fq) by D-glutamine addition to CCQDs solution and ∆Fq was well linear with D-glutamine concentration in the range of 0.01-5.0 mM with a detection limit of 0.28 mM. Calculation of the binding energy between L/D-glutamine and CCQDs by molecular modelling to explain the chiral recognition mechanism[2,3]. The method was applied to the determination of L-glutamine content in real sample and the results showed good recoveries, indicating the feasibility of the method. References: [1] F. Copur, N. Bekar, E. Zor, S. Alpaydin, H. Bingol, Nanopaper-based photoluminescent enantioselective sensing of L-Lysine by L-Cysteine modified carbon quantum dots, Sensors and Actuators B: Chemical. 279 (2019) 305–312. https://doi.org/10.1016/j.snb.2018.10.026. [2] O. Xu, S. Wan, Y. Zhang, J. Li, X. Zhu, A unique dual-excitation carbon quantum dots: Facile synthesis and application as a dual-“on-off-on” fluorescent probe, Sensors and Actuators B: Chemical. 340 (2021) 129904. https://doi.org/10.1016/j.snb.2021.129904. [3] X. Hou, J. Song, Q. Wu, H. Lv, Chiral carbon quantum dots as fluorescent probe for rapid chiral recognition of isoleucine enantiomers, Analytica Chimica Acta. 1184 (2021) 339012. https://doi.org/10.1016/j.aca.2021.339012.