Analytical Chemistry Department, Faculty of Pharmacy, University of Sadat City, Sadat City, Monufia, 32897, Egypt.
Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Mansoura University, Mansoura, 35526, Egypt.
Methods Appl Fluoresc. 2023 Aug 25;11(4). doi: 10.1088/2050-6120/acf119.
Green, one-pot, quick, and easily synthesized nitrogen and sulfur co-doped carbon quantum dots (N,S-CDs) were obtained from cheap and readily available chemicals (sucrose, urea, and thiourea) using a microwave-assisted approach in about 4 min and utilized as a turn-off fluorescent sensor for estimation of natamycin (NAT). First, the effect of N and S doping on the microwave-synthesized CDs' quantum yield was carefully studied. CDs derived from sucrose alone failed to produce a high quantum yield; then, to increase the quantum yield, doping with heteroatoms was carried out using either urea or thiourea. A slight increase in quantum yield was observed upon using thiourea with sucrose, while an obvious enhancement of quantum yield was obtained when urea was used instead of thiourea. Surprisingly, using a combination of urea and thiourea together results in N,S-CDs with the highest quantum yield (53.5%), uniform and small particle size distribution, and extended stability. The fluorescent signal of N,S-CDs was quenched upon addition of NAT due to inner filter effect and static quenching in a manner that allowed for quantitative determination of NAT over a range of 0.5-10.0g ml(LOD = 0.10g ml). The N,S-CDs were applicable for determination of NAT in aqueous humor, eye drops, different environmental water samples, and bread with excellent performance. The selectivity study indicated excellent selectivity of the prepared N,S-CDs toward NAT with little interference from possibly interfering substances. In-silico toxicological evaluation of NAT was conducted to estimate its long-term toxicity and drug-drug interactions. Finally, the preparation of N,S-CDs, and analytical procedure compliance with the green chemistry principles were confirmed by two greenness assessment tools.
绿色、一锅法、快速且易于合成的氮硫共掺杂碳量子点（N,S-CDs）是由廉价易得的化学品（蔗糖、尿素和硫脲）通过微波辅助法在约 4 分钟内合成的，并用作关闭荧光传感器来估计纳他霉素（NAT）。首先，仔细研究了 N 和 S 掺杂对微波合成的 CDs 量子产率的影响。单独使用蔗糖合成的 CDs 无法产生高量子产率；然后，为了提高量子产率，使用杂原子（尿素或硫脲）进行掺杂。使用蔗糖与硫脲掺杂时，量子产率略有增加，而使用尿素代替硫脲时，量子产率明显提高。令人惊讶的是，使用尿素和硫脲的组合可以得到具有最高量子产率（53.5%）、均匀且小的粒径分布和延长稳定性的 N,S-CDs。由于内滤效应和静态猝灭，N,S-CDs 的荧光信号在添加 NAT 后被猝灭，可以在 0.5-10.0g ml（LOD=0.10g ml）范围内定量测定 NAT。N,S-CDs 可用于测定水样、滴眼液、不同环境水样和面包中的 NAT，具有优异的性能。选择性研究表明，所制备的 N,S-CDs 对 NAT 具有优异的选择性，几乎没有可能干扰物质的干扰。对 NAT 进行了基于计算机的毒理学评价，以估计其长期毒性和药物相互作用。最后，通过两种绿色评估工具证实了 NAT 的制备、N,S-CDs 的分析程序符合绿色化学原则。
