L-Histidine

Carbon dots (CDs) were highly promised nanomaterials for application in food analysis, owing to their exceptional optical properties, superior photostability, and negligible biological toxicity. N-doped CDs (NCDs) were synthesized via a straightforward hydrothermal method utilizing folic acid as only one precursor material. NCDs exhibited deep blue fluorescence under an ultraviolet lamp with a quantum yield (QY) of 14.54 %. In the presence of arginine (Arg), there was a noticeable redshift of 10 nm in the maximum emission wavelength of NCDs, accompanied by fluorescence transition from dark blue to bright blue. The QY of NCDs was 16.71 % in the presence of Arg. In other words, NCDs showed aggregation-induced emission enhancement (AIEE) in the presence of Arg. The fluorescence enhancement exhibited a strong linear correlation with Arg concentration within the range of 0-300 μM, and the limit of detection was 0.31 μM. Furthermore, to facilitate Arg detection, a portable Arg sensor was developed using a polyvinyl alcohol membrane-assisted design. The sensor demonstrated satisfactory performance in detecting Arg in real samples. These findings highlighted the versatile capabilities of NCDs with AIEE properties, paving the way for their potential applications in food analysis.

Dichlorprop (DCPP), a chlorophenoxy herbicide with two enantiomers, shows distinct biological and toxicological properties: R-DCPP is highly effective as a herbicide, while S-DCPP lacks herbicidal activity and is toxic to non-target organisms. Efficient enantioseparation methods for DCPP are crucial for precise herbicide use, reduced agrochemical consumption, and minimized environmental impact. To achieve this purpose, a novel capillary monolithic column (L-His-ZIF-8@CMIP(rac-DCPP/PG-EDMA)@capillary) was fabricated using the nanomaterials synthesized by chiral molecularly imprinted polymers (CMIPs) and chiral metal-organic frameworks (CMOFs, L-His-ZIF-8) as stationary phases. Based on this innovative column, a capillary electrochromatography (CEC) system was established, enabling highly efficient enantioseparation of DCPP, precise chiral purity determination, and accurate quantitative analysis of individual enantiomers in complex real-world samples. During the synthesis of CMIPs, a novel functional monomer, allyl-β-d-Pyrone galactoside (PG), demonstrated unique "pre-chiral recognition" capability towards the racemic template (rac-DCPP) in the CMIP premix. This innovative approach enabled the successful synthesis of chirally selective CMIPs using rac-DCPP as template, rather than conventional single-enantiomer templates, in combination with ethylene dimethacrylate (EDMA) as the cross-linker. This synthesis strategy offers significant advantages, including substantial reduction in production costs and simplified synthesis procedures. To the best of our knowledge, this represents the first reported application of such methodology in CEC worldwide, as confirmed by comprehensive literature review. L-His-ZIF-8@CMIP(rac-DCPP/PG-EDMA)@capillary demonstrates remarkable enantioseparation capabilities through synergistic interactions between its components. Furthermore, the enantioseparation mechanism was systematically investigated through molecular docking and static adsorption experiments, providing fundamental insights into the chiral recognition process. This study establishes a groundbreaking approach for the development of racemic template-based CMIPs and the synthesis of advanced chiral stationary phases, offering significant potential for practical applications in chiral separation science.