A novel ratiometric fluorescent probe for detection of l-glutamic acid based on dual-emission carbon dots

In this article, we report for the first time the use of a dual-emission carbon dots (CDs) with orange-yellow fluorescence for the detection of l-glutamic acid (L-Glu). The CDs was synthesized through a facile strategy of one-pot hydrothermal route using o-phenylenediamine (oPD) and oxalic acid. The CDs exhibit two fluorescence emission peaks around 453 nm and 560 nm when the excitation wavelength is at 390 nm. In the existence of L-Glu the fluorescence at 560 nm was decreased, whereas the fluorescence at 453 nm was constant. The fluorescence intensity ratio at 560 nm and 453 nm (F₅₆₀/F₄₅₃) expressed two great linear relationships in the L-Glu concentration range from 0 to 200 μM and 200-400 μM, respectively, with a detection limit (LOD) of about 0.085 μM. In addition, it was used to analyze L-Glu in fetal bovine serum samples successfully, which recoveries were ranging from 97.07 to 103.7%. Those results demonstrate CDs can be further explored in biomedicine studies.