São Paulo State University (UNESP), National Institute for Alternative Technologies of Detection, Toxicological Evaluation and Removal of Micropollutants and Radioactives (INCT-DATREM), Department of Chemistry and Environmental Science, 15054-000, São José do Rio Preto, SP, Brazil.
Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, 13565-905, São Carlos, SP, Brazil.
Talanta. 2020 Aug 15;216:120956. doi: 10.1016/j.talanta.2020.120956. Epub 2020 Apr 2.
Solvents with both low density and viscosity have the advantage of higher extraction efficiency due to lower diffusivity and consequently higher mass transfer. In this study, a mixture design was performed for the synthesis of three different natural deep eutectic solvents (NADES) using citric acid, malic acid, and xylitol. The optimized proportion for each of the three solvents synthesized was selected based on density and viscosity values. The NADES were characterized by infrared spectroscopy analysis, that showed characteristic bands of the initial reagents and the presence of hydrogen bonds confirming the formation of each deep eutectic solvent. Then, the NADES were used as solvents in ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) of biological tissue and plant material samples for the determination of As, Cd, Hg, Pb, Se, and V by inductively coupled plasma mass spectrometry (ICP-MS). The results for the proposed methods were compared to microwave-assisted acid digestion (MW-AD). The extraction recoveries ranged from 80 to 120% for most of the elements determined. The use of NADES as carbon sources improved the sensitivity of the As and Cd analyses, due to charge transfer reactions between the analyte and C and/or other carbon species. In addition, the Analytical Eco-Scale was used to assess the greenness of the proposed analytical procedures (UAE and MAE). It showed that the UAE and MAE methods provided excellent green analyses, while the MW-AD method was rated as an acceptable green procedure.
溶剂具有低的密度和粘度的优势具有更高的提取效率由于较低的扩散系数和因此更高的传质。在这项研究中，使用柠檬酸、苹果酸和木糖醇进行了三种不同天然深共晶溶剂（NADES）的合成的混合物设计。根据密度和粘度值选择了每种溶剂合成的最佳比例。NADES 通过红外光谱分析进行了表征，该分析显示了初始试剂的特征带和氢键的存在，证明了每种深共晶溶剂的形成。然后，NADES 被用作超声辅助提取 (UAE) 和微波辅助提取 (MAE) 生物组织和植物材料样品的溶剂，用于通过电感耦合等离子体质谱法 (ICP-MS) 测定 As、Cd、Hg、Pb、Se 和 V。所提出的方法的结果与微波辅助酸消解 (MW-AD) 进行了比较。对于大多数测定的元素，提取回收率在 80%至 120%之间。由于分析物与 C 和/或其他碳物种之间的电荷转移反应，NADES 作为碳源的使用提高了 As 和 Cd 分析的灵敏度。此外，还使用分析生态规模来评估所提出的分析程序（UAE 和 MAE）的绿色性。结果表明，UAE 和 MAE 方法提供了极好的绿色分析，而 MW-AD 方法被评为可接受的绿色程序。
