Department of Analytical Chemistry and Food Science and University Institute of Materials, University of Alicante, P.O. Box 99, 03080 Alicante, Spain.
Department of Bioengineering, University of Illinois at Urbana-Champaign, United States.
Food Chem. 2019 Jan 30;272:141-147. doi: 10.1016/j.foodchem.2018.08.002. Epub 2018 Aug 9.
A rapid and portable analytical methodology has been developed for ascorbic acid (Vitamin C) quantification from aqueous samples using a spectrometric smartphone-based system for the first time. The method employs point-of-use approaches both for sample preparation and sample measurement, demonstrating the capability for mobile quality control of pharmaceutical and food products. Our approach utilizes an oxidation-reduction reaction between ascorbic acid and methylene blue, followed by a dispersive liquid-liquid microextraction (DLLME) to extract the aqueous-phase methylene blue into organic media. Then, a back-extraction procedure is employed to transfer the methylene blue to aqueous media, followed by analysis of the sample's absorption spectrum using the spectrometric smartphone-based system. The DLLME and back-extraction procedures are optimized by use of a two-step multivariate optimization strategy. Finally, vitamin C supplements and orange juice are used as real-world samples to assess the applicability of the smartphone-based method, which is successfully compared with the standard laboratory-based approach.
首次开发了一种快速便携的分析方法，用于通过基于智能手机的分光光度系统从水样中定量测定抗坏血酸（维生素 C）。该方法既用于样品制备又用于样品测量的现场检测方法，展示了对药品和食品进行移动质量控制的能力。我们的方法利用抗坏血酸和亚甲基蓝之间的氧化还原反应，然后通过分散液液微萃取（DLLME）将水相中亚甲基蓝萃取到有机相中。然后，采用反萃取程序将亚甲基蓝转移到水相，再使用基于智能手机的分光光度系统分析样品的吸收光谱。通过两步多元优化策略对 DLLME 和反萃取程序进行了优化。最后，使用维生素 C 补充剂和橙汁作为实际样品来评估基于智能手机的方法的适用性，并成功与基于标准实验室的方法进行了比较。
