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 for Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, 13565-905 São Carlos, SP, Brazil.
Talanta. 2019 Jul 1;199:361-369. doi: 10.1016/j.talanta.2019.02.083. Epub 2019 Feb 25.
Natural deep eutectic solvents (NADES) based on xylitol, citric acid, and malic acid were synthesized and were then characterized using infrared spectroscopy, thermogravimetry (TG), differential scanning calorimetry (DSC), also density and viscosity were measurements. The deep eutectic solvents were used as solvent in ultrasound-assisted extraction (DES-UAE) of plant samples prior to elemental analysis. Inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-optical emission spectrometry (ICP OES) were employed for the determination of As, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, P, and Zn in the extracts. The infrared analyses of the NADES revealed bands characteristic of the initial reagents, with the presence of hydrogen bonds, which confirmed the formation of a NADES. The thermal analyses showed decomposition temperatures of around 170 °C and endothermic events related to degradation of the NADES. The viscosity and density parameters were found to be related to the presence of hydrogen bonds. The extraction recoveries ranged from 80% to 120%, with some analytes presenting poor recoveries. There were no significant differences between the NADES, in terms of the concentrations of the analytes found in the extracts. However, there were differences between the analyte concentrations obtained using the NADES extraction method and the concentrations obtained using microwave-assisted acid digestion (MW-AD), possibly due to the different types of interactions between the solvents and the analytes. Plant tissues are complex matrices containing substantial amounts of silica, so some elements may be tightly bound and consequently difficult to release. The results indicated that UAE using NADES is a promising technique for the elemental extraction of plant samples.
基于木糖醇、柠檬酸和苹果酸的天然深共熔溶剂（NADES）被合成出来，并使用红外光谱、热重分析（TG）、差示扫描量热法（DSC）以及密度和粘度测量进行了表征。深共熔溶剂在元素分析之前被用作超声辅助提取（DES-UAE）植物样品的溶剂。电感耦合等离子体质谱（ICP-MS）和电感耦合等离子体发射光谱（ICP OES）被用于测定提取物中的砷、钙、镉、铜、铁、钾、镁、锰、钠、磷和锌。NADES 的红外分析显示出与初始试剂特征相关的谱带，存在氢键，这证实了 NADES 的形成。热分析表明，分解温度约为 170°C，并且存在与 NADES 降解相关的吸热事件。粘度和密度参数与氢键的存在有关。萃取回收率在 80%到 120%之间，有些分析物的回收率较差。在提取物中分析物浓度方面，NADES 之间没有显著差异。然而，在使用 NADES 萃取方法和使用微波辅助酸消解（MW-AD）获得的分析物浓度之间存在差异，这可能是由于溶剂和分析物之间的不同类型的相互作用。植物组织是含有大量二氧化硅的复杂基质，因此某些元素可能紧密结合，因此难以释放。结果表明，使用 NADES 的 UAE 是一种很有前途的植物样品元素提取技术。
