Smartphone assisted high-performance fluorescence/colorimetric dual-mode enantioselective identification of glutamic acid in complex samples

Abstract

Identification and detection of glutamic acid (Glu) enantiomers play a crucial role in the food industry, pharmaceutical processing, and disease diagnosis. However, due to their similar structures, the specific discrimination and detection of D/L-Glu are still major challenges. To address this, new carbon dots N-NCDs were prepared in this work; importantly, N-NCDs exhibited rapid, sensitive, and highly specific responses to Glu enantiomers, even in the presence of other amino acids (AAs) or interfering ions, whether in fluorescent or colorimetric mode. This probe exhibited significant enantioselectivity for D/L-Glu, with fluorescence (F_D/F_L) and colorimetric (I_L/I_D) enantioselectivity values of 3.66 and 7.68, respectively. Additionally, the response of N-NCDs to Glu enantiomers is accompanied by obvious color changes, offering rapid and visual detection capabilities. Smartphone-assisted dual-mode analysis was able to reduce experimental errors associated with single-mode assays, and minimized variability introduced by different instrumental procedures, thereby improving the overall detection accuracy. Notably, N-NCDs also demonstrated excellent selectivity and reproducibility in detecting D/L-Glu in real samples, highlighting its promising potential for accurate detection of Glu enantiomers in a complex matrix.