Monte-Filho Severino S, Andrade Stefani I E, Lima Marcelo B, Araujo Mario C U
Universidade Federal da Paraíba, CCEN, Departamento de Química, P.O. Box 5093, Zip Code 58051-970, João Pessoa, PB, Brazil.
Universidade Federal Rural de Pernambuco - Unidade Acadêmica de Serra Talhada, UAST, Zip Code 56909-535, Serra Talhada, PE, Brazil.
J Pharm Anal. 2019 Jun;9(3):209-216. doi: 10.1016/j.jpha.2019.02.003. Epub 2019 Feb 27.
In this work, lemon and onion biomasses commonly found in street markets are for the first time used to develop a facile, fast and low-cost one-step microwave-assisted carbonization method for synthesis of highly fluorescent carbon dots (CDs). The structure and optical properties of CDs were investigated by TEM, XRD, XRF, UV-Vis, FTIR, and fluorescence spectroscopy. CDs displayed satisfactory optical proprieties, a high quantum yield of 23.6%, and excellent water solubility, and the particle size was 4.23-8.22 nm with an average diameter of 6.15 nm. An efficient fluorescent resonance energy transfer (FRET) between the CDs and riboflavin was achieved with CDs acting as donor and riboflavin as acceptor. A linear relationship between FRET and the riboflavin concentration from 0.10 to 3.0 μg/mL was observed, allowing the development of an accurate and fast analytical method to determine this vitamin in multivitamin/mineral supplements. Despite the potential interferences in these supplements, CDs were selective for riboflavin under optimized conditions. A paired -test at a 95% confidence level indicated no statistically significant difference between the proposed and the reference methods. Recovery test presented values ranged from 96.0% to 101.4%. The limit of detection and relative standard deviation were estimated at 1.0 ng/mL and <2.6% ( = 3), respectively. CDs were successfully synthesized in a domestic microwave oven (1450 W, 6 min), presenting satisfactory parameters when compared with results of other studies reported in the literature, suggesting that the proposed method is a potentially useful method for the synthesis of CDs and determination of riboflavin.
在本研究中，首次利用街头市场常见的柠檬和洋葱生物质，开发了一种简便、快速且低成本的一步微波辅助碳化法，用于合成高荧光碳点（CDs）。通过透射电子显微镜（TEM）、X射线衍射（XRD）、X射线荧光光谱（XRF）、紫外可见光谱（UV-Vis）、傅里叶变换红外光谱（FTIR）和荧光光谱对碳点的结构和光学性质进行了研究。碳点表现出令人满意的光学性能，量子产率高达23.6%，且具有优异的水溶性，粒径为4.23 - 8.22纳米，平均直径为6.15纳米。以碳点为供体、核黄素为受体，实现了碳点与核黄素之间高效的荧光共振能量转移（FRET）。观察到FRET与核黄素浓度在0.10至3.0μg/mL之间呈线性关系，从而开发出一种准确、快速的分析方法，用于测定多种维生素/矿物质补充剂中的这种维生素。尽管这些补充剂中存在潜在干扰，但在优化条件下，碳点对核黄素具有选择性。在95%置信水平下的配对检验表明，所提出的方法与参考方法之间没有统计学上的显著差异。回收率测试结果在96.0%至101.4%之间。检测限和相对标准偏差分别估计为1.0 ng/mL和<2.6%（n = 3）。碳点在家用微波炉（1450 W，6分钟）中成功合成，与文献报道的其他研究结果相比，呈现出令人满意的参数，表明所提出的方法是一种合成碳点和测定核黄素的潜在有用方法。
