Researchers have investigated different techniques for synthesis of carbon dots. These techniques include Arc discharge, laser ablation, oxidation, water/solvothermal, and chemical vapor deposition. However, these techniques suffer from some limitations like the utilization of gaseous charged particles, high current, high temperature, potent oxidizing agents, non-environmentally friendly carbon sources, and the generation of uneven particle size. Therefore, there was a significant demand for the adoption of a new technology that combines the environmentally friendly aspects of both bio-based carbon sourcing and synthesis technique. L (alfalfa)-derived N, S-CDs have been successfully synthesized via microwave irradiation. The N,S-CDs exhibit strong fluorescence ( of 320/420 nm) with fluorescence quantum yield of 2.2 % and high-water solubility. The produced N,S-CDs were characterized using TEM, EDX, Zeta potential analysis, IR, UV–Visible, and fluorescence spectroscopy. The average diameter of the produced N, S-CDs was 4.01 ± 1.2 nm, and the Zeta potential was −24.5 ± 6.63 mv. The stability of the produced nano sensors was also confirmed over wide pH range, long time, and in presence of different ions. The synthesized N, S-CDs were employed to quantify the antibacterial drug, nifuroxazide (NFZ), by fluorescence quenching via inner filter effect mechanism. The method was linear with NFZ concentration ranging from 1.0 to 30.0 μM. LOD and LOQ were 0.16 and 0.49 μM, respectively. The method was applied to quantify NFZ in simulated gastric juice (SGJ) with % recovery 99.59 ± 1.4 in addition to pharmaceutical dosage forms with % recovery 98.75 ± 0.61 for Antinal Capsules® and 100.63 ± 1.54 for Antinal suspension®. The Method validation was performed in compliance with the criteria outlined by ICH. The suggested approach primarily centers on the first-time use of alfalfa, an ecologically sustainable source of dopped-CDs, and a cost-effective synthesis technique via microwave irradiation, which is characterized by low energy consumption, minimized reaction time, and the ability to control the size of the produced CDs. This is in line with the growing global recognition of the implementation of green analytical chemistry principles.

中文翻译：

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苜蓿生物质作为通过微波处理合成 N,S-CD 的绿色来源。作为硝呋嗪纳米传感器在制剂和胃液中的应用


研究人员研究了不同的碳点合成技术。这些技术包括电弧放电、激光烧蚀、氧化、水/溶剂热和化学气相沉积。然而，这些技术受到一些限制，例如使用气态带电粒子、高电流、高温、强氧化剂、不环保的碳源以及产生不均匀的粒径。因此，迫切需要采用一种结合生物基碳源和合成技术的环保方面的新技术。 L（苜蓿）衍生的 N,S-CD 已通过微波辐射成功合成。 N,S-CD 表现出强荧光（320/420 nm），荧光量子产率为 2.2%，水溶性高。使用 TEM、EDX、Zeta 电位分析、红外、紫外-可见光和荧光光谱对产生的 N,S-CD 进行表征。生成的N、S-CD的平均直径为4.01±1.2nm，Zeta电位为-24.5±6.63mv。所生产的纳米传感器在较宽的 pH 范围、长时间和不同离子存在下的稳定性也得到了证实。合成的 N、S-CD 用于通过内滤效应机制的荧光猝灭来定量抗菌药物硝呋嗪 (NFZ)。该方法与 1.0 至 30.0 μM 的 NFZ 浓度呈线性关系。 LOD 和 LOQ 分别为 0.16 和 0.49 μM。该方法用于定量模拟胃液 (SGJ) 中的 NFZ，回收率百分比为 99.59 ± 1.4，此外，药物剂型的 Antinal Capsules® 回收率百分比为 98.75 ± 0.61，Antinal 悬浮液® 回收率百分比为 100.63 ± 1.54。 方法验证是按照 ICH 概述的标准进行的。建议的方法主要集中在首次使用苜蓿（一种生态上可持续的掺杂 CD 来源）以及通过微波辐射进行的具有成本效益的合成技术，其特点是能耗低、反应时间最短，并且能够控制制作的 CD 的大小。这符合全球对实施绿色分析化学原则日益增长的认识。