离子液体基磁性固相萃取技术的研究进展

磁性固相萃取(Magnetic solid-phase extraction,MSPE)是一种采用磁性材料作为吸附剂的新型样品前处理技术,发展新型的磁性材料作为吸附剂是MSPE领域的研究热点。用离子液体(Ionic liquid,IL)修饰磁性材料作为吸附剂既具有MSPE操作简单、萃取快速、基质干扰小的优点,又兼具IL结构的可设计性和易功能化的优点,在样品前处理领域引起了广泛关注。该文综述了IL修饰磁性吸附剂的制备方法(物理涂敷、化学键合和包埋法),IL-MSPE的萃取方式(传统的MSPE,混合半胶束-MSPE和分散液液微萃取-MSPE),以及IL-MSPE在有机污染物、金属离子和生物活性物质萃取分离中的应用,并对该技术的发展趋势进行了展望。     

低共熔溶剂液-液微萃取/高效液相色谱法检测饮料和糖果中10种水溶性色素EI北大核心CSCD

以不同氢键供体和氢键受体合成的10种疏水型低共熔溶剂(DES)作为溶剂提取食品中合成色素,辅助液-液微萃取前处理技术,建立同时测定10种水溶性色素的高效液相色谱方法。结果表明:由四丁基氯化铵和辛酸合成的低共熔溶剂提取色素的效果最好,在最佳萃取条件(含水量0,摩尔比1∶3,提取剂用量500μL,提取温度20℃、振摇时间20 min)下,色素的回收率达83.5%~119.8%,仪器检出限为11.3~500.0μg/L。应用建立的方法测定汽水和糖果中的色素,赤藓红加标回收率在40%左右,其余色素加标回收率在77.8%~102.7%之间,相对标准偏差小于5.3%。     

基于低共熔溶剂的多孔有机框架材料合成及其在固相萃取中的应用北大核心CSCD

本文综述了低共熔溶剂(DES)在多孔有机框架材料(POFs)中金属有机框架(MOFs)和共价有机框架(COFs)合成方面的应用,以及这些新型材料在固相萃取领域的潜在应用。DES作为环保绿色溶剂,不仅用于MOFs和COFs的制备,还在特定情况下作为结构导向剂,对框架的结构和性能产生重要影响。通过合适的DES配方,研究人员能够调控MOFs和COFs的晶体结构、孔径和表面性质,从而获得性能卓越的材料。MOFs和COFs因其具有较大的比表面积和丰富的活性位点,在固相萃取中展现出卓越的吸附能力和选择性,能够有效地从复杂样品中富集目标分析物。研究证明,基于DES的MOFs和COFs在环境分析、食品检测和生物样品分析等领域具有广泛的应用潜力。尽管基于DES的MOFs和COFs在固相萃取领域仍处于初级阶段,但其高效富集和高选择性等特性为实际应用提供了良好前景。未来的研究应继续深入探索基于DES的合成方法,以制备更多性能卓越的MOFs和COFs,并深入研究其在各个领域的应用潜力。这些努力有望将这些新型材料应用于商业化的固相萃取方法中,为分析化学领域带来新的发展机遇。     

基于低共熔溶剂的分散液液微萃取/超高效液相色谱-串联质谱法测定马肉中非甾体抗炎药

采用氯化胆碱和苯酚合成低共熔溶剂(DES),以其为萃取剂建立了分散液液微萃取(DLLME)结合超高效液相色谱-串联质谱(UPLC-MS/MS)测定马肉中10种非甾体抗炎药的方法。优化了提取溶剂、萃取剂、分散剂和盐的加入量等条件,最佳萃取条件为：以氯化胆碱和苯酚(比例为1∶2)合成的低共熔溶剂为萃取剂,马肉样品经5 mL含10 mmol/L抗坏血酸的20 mmol/L醋酸铵缓冲液(乙酸调至pH 3.5)提取,加入1.0 g氯化钠、0.8 mL萃取剂和0.8 mL分散剂,旋涡混合1 min,离心后取上清液经超高效液相色谱-串联质谱测定,外标法定量。结果显示,10种非甾体抗炎药在各自质量浓度范围内呈良好线性关系,相关系数(r2)均大于0.996,检出限为0.05~2.0 μg/kg,定量下限为0.10~5.0 μg/kg,平均回收率为73.5%~94.6%,相对标准偏差(RSD)为1.1%~8.1%。该方法操作简单、准确高效、绿色环保,可用于马肉中非甾体抗炎药的测定。     

低共熔溶剂在萃取分离中的应用

随着绿色化学的不断发展,如何在分析过程中应用和体现绿色化学特点,避免分析过程对环境产生二次污染及对人员造成危害也得到了关注。开发和使用具有绿色化学特点的溶剂和方法是分析工作者努力的方向之一。在已经出现的新溶剂中,低共熔溶剂(DES)与离子液体(ILs)物理性质相似,并具有环境友好、不可燃、生物降解、价廉、易制备等特点,因而近几年来获得了迅速发展。该文总结了低共熔溶剂的制备、性质及分类,综述了近年来其在萃取和分离中的应用进展。     

基于超声辅助原位生成低共熔溶剂的分散液-液微萃取-悬浮固化结合毛细管电泳测定环境水样中氟喹诺酮

基于超声辅助原位生成低共熔溶剂（DES）的分散液-液微萃取-悬浮固化（UA-IF-DLLMESFDES）并结合大体积样品堆积毛细管电泳,建立了对环境水样中加替沙星、洛美沙星、环丙沙星和氟罗沙星4种氟喹诺酮类药物（FQs）进行萃取和测定的新方法。实验筛选出甲基三辛基溴化铵作为氢键受体（HBA）,庚酸为氢键供体（HBD）,以原位生成方法制备的DES为萃取剂,并对DES的种类及用量、原位生成条件、盐用量、涡旋时间等影响萃取效率的实验条件进行了优化。结果表明,在最佳实验条件下,4种目标物的检出限（S/N=3）和定量下限（S/N=10）分别为0.6～5.5μg/L和2.0～18.3μg/L,富集倍数为89～129,日内和日间相对标准偏差（RSD）分别为3.5%～5.9%和4.5%～7.1%,加标回收率为75.6%～110%。所建立的方法成功应用于实际水样中4种FQs的检测。     

分散液液微萃取-气相色谱法测定水样中甲拌磷农药

建立了基于分散液液微萃取(DLLME)的新型样品前处理方法,并采用气相色谱/氢火焰离子化检测器对水样中痕量的甲拌磷农药进行了测定。考察了影响分散液液微萃取的因素包括萃取溶剂、分散剂、样品体积、萃取温度和离心速度等。在最佳实验条件下,对甲拌磷的富集倍数达到300倍;检出限为0.001μL/L;方法的线性范围为0.01~10μL/L,R2为0.9986;相对标准偏差为6.65%;回收率为104%。将分散液液微萃取法与单滴液相微萃取和离子液体-液相微萃取方法进行了对比,结果表明,分散液液微萃取技术具有操作简单、快捷(前处理时间小于5 min)、富集效果好、回收率高等优点。同时预言,将离子液体与分散液液微萃取结合,将会产生更加满意的结果。     

离子液体和氯代溶剂分散液-液微萃取/高效液相色谱法联用富集和分析环境水样中酞酸酯类污染物的对比研究

以4种室温离子液体和4种氯代溶剂为萃取剂,与高效液相色谱(HPLC)联用,对比研究了分散液-液微萃取(DLLME)对5种痕量酞酸酯类化合物(PAEs)的富集分离性能。以1-辛基-3-甲基咪唑六氟磷酸盐([OMim][PF6])和建议研究四氯化碳替代品为典型萃取溶剂优化了萃取条件。结果表明,在1.00～100μg/L范围内色谱峰面积与PAEs浓度成良好的线性关系(相关系数>0.995);对于10.0μg/L加标混合样品,平均加标回收率88.2%～103.3%,RSD在2.1%～6.8%之间(n=5),LOD在0.01～0.08μg/L范围内(S/N=3)。与四氯化碳相比,[OMim][PF6]作为DLLME的萃取溶剂对PAEs的富集倍数较高,水相盐效应影响较小。超声波辅助微萃取(USA)可在2 min达到平衡,建立的USA-DLLME-HPLC方法可用于黄河水样和城生活区污水样品中痕量PAEs的富集分离和测定。     

磁性固相萃取技术研究的新进展

基于磁性材料的分离技术是近年来国内外研究的一个热点领域,该技术在细胞分离、药物转运、酶的固定化、催化、吸附-分离、材料科学、环境等诸多领域中都展示了应用前景。磁性纳米材料可作为磁性固相萃取(MSPE)的吸附剂。与常规的固相萃取(SPE)柱填料相比,纳米粒子的比表面积大、扩散距离短,只需使用少量的吸附剂和较短的平衡时间就能实现萃取分离,因此具有较高的萃取能力和萃取效率。经功能化修饰,磁性吸附剂有望实现对分析物的选择性萃取。另外,磁性吸附剂经适当的润洗之后可以循环使用。MSPE仅通过施加一个外部磁场即可实现相分离,因此操作简单、省时快速、无需离心过滤等繁琐操作,避免了传统SPE吸附剂需装柱和样品上样等耗时问题,而且在处理生物、环境样品时不会存在SPE中遇到的柱堵塞的问题。MSPE技术在痕量污染物萃取分离领域已得到了应用［1,2］。本文对MSPE技术研究的最新进展做一简要介绍。     

金属有机骨架复合材料在样品预处理中的研究进展

金属有机骨架（MOFs）材料是近几年涌现出的一类新型多功能多孔材料,以金属离子或金属簇为配位中心,与含氧或氮的有机配体通过配位作用形成多孔骨架结构。相比于其他传统无机多孔材料,MOFs具有比表面积高、孔隙率大、热稳定性好和结构与功能多样化的特点,因而被广泛用于气体存储、催化、吸附和分离等领域。MOFs复合材料在样品预处理方面的应用引起了研究者们的极大兴趣和广泛关注。由于MOFs材料和不同功能材料如高分子聚合物、碳基材料以及磁性材料组装复合,使MOFs复合材料的性能优于原来的MOFs材料。综述了近年MOFs复合材料在样品预处理的研究应用,尤其是在固相微萃取、固相萃取以及磁性固相萃取等方面的应用。     

Revisiting the Physicochemical Properties and Applications of Deep Eutectic Solvents

Recently, deep eutectic solvent (DES) or ionic liquid (IL) analogues have been considered as the newest green solvent, demonstrating the potential to replace harsh volatile organic solvents. DESs are mainly a combination of two compounds: hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD), which have the ability to interact through extensive hydrogen bonds. A thorough understanding of their physicochemical properties is essential, given their successful applications on an industrial scale. The appropriate blend of HBA to HBD can easily fine-tune DES properties for desired applications. In this context, we have reviewed the basic information related to DESs, the two most studied physicochemical properties (density and viscosity), and their performance as a solvent in (i) drug delivery and (ii) extraction of biomolecules. A broader approach of various factors affecting their performance has been considered, giving a detailed picture of the current status of DESs in research and development.     

低共熔溶剂：一种应用在混合物分离过程中的绿色溶剂

低共熔溶剂(DESs)因具有合成容易、价格低廉、环境友好、挥发性低、溶解能力强、可生物降解、结构可设计等特点,被认为是一种绿色溶剂。近年来,研究者通过深入研究低共熔溶剂的性质,结合低共熔溶剂的特点,将其替代传统的有机溶剂,在混合物分离过程中开展了大量的研究工作,包括：酸性气体(如CO₂、CO₂和H₂S)吸收、生物活性物质萃取、燃料油品中含硫和含氮化合物的脱除、油酚混合物分离、芳烃和脂肪烃混合物的分离、醇水混合物分离、生物柴油合成过程中甘油的脱除等。本文分析了低共熔溶剂的结构、性质和特点,综述了低共熔溶剂在分离领域的最新研究成果,探讨了低共熔溶剂在混合物分离应用中存在的问题,展望了低共熔溶剂的发展趋势。     

深共熔溶剂同步提取红景天中红景天苷和酪醇

采用深共熔溶剂(Deep eutectic solvents, DESs)法同步提取红景天中红景天苷和酪醇. 首先, 通过对氢键供体(HBD)、 氢键受体(HBA)及二者摩尔比和DESs含水量等因素的设计优化, 获得了同步提取红景天苷和酪醇的最佳DES为乙二醇-乙酰丙酸(摩尔比为1∶1), 含水质量分数为40%, 记为LAEG-40. 然后, 以LAEG-40作提取溶剂, 对提取方法、 料液比、 提取温度及提取时间等因素进行优化, 获得了最佳提取条件: 采用150 r/min搅拌速率提取, 料液比为1∶12.5(g/mL), 提取温度60 ℃, 提取时间65 min. 在此条件下LAEG-40对红景天苷的提取率可达(18.1268±0.1667) mg/g, 酪醇提取率可达(1.5608±0.0240) mg/g. 而在相同条件下, 以水和乙醇作为提取溶剂, 红景天苷提取率分别为(15.1221±0.1342)和(16.3425±0.0897) mg/g, 酪醇提取率分别为(1.1120±0.0389)和(1.1923±0.0423) mg/g, 可见LAEG-40的提取效果明显高于传统溶剂. 研究结果表明, LAEG-40是一种绿色、 高效的红景天苷和酪醇同步提取溶剂, 可用于替代传统溶剂.     

The electrochemical stability of ionic liquids and deep eutectic solvents

Room temperature ionic liquids (ILs) composed of cations and anions, as well as deep eutectic solvents (DESs) composed of hydrogen bond donors (HBDs) and hydrogen bond acceptors (HBAs), are regarded as green solvents due to their low volatility. They have been used widely for electrochemically driven reactions because they exhibit high conductivity and excellent electrochemical stability. However, no systematic investigations on the electrochemical potential windows (EPWs), which could be used to characterize the electrochemical stability, have been reported. In this regard, the EPWs of 33 ILs and 23 DESs have been studied utilizing cyclic voltammetry (CV) method and the effects of structural factors (cations and anions of ILs, and HBDs and HBAs of DESs) and external factors (electrode, water content) on the EPWs have been comprehensively investigated. The electrochemical stability of selected ILs comprising five traditional cations, namely imidazolium, pyridinium, pyrrolidinium, piperidinium and ammonium and 13 kinds of versatile anions was studied. The results show that for ILs, both cation and anion play an important role on the reductive and oxidative potential limit. For a same IL at different working electrode, for example, glassy carbon (GC), gold (Au) and platinum (Pt) electrode, the largest potential window is almost observed on the GC working electrode. The investigations on the EPWs of choline chloride (ChCl), choline bromide (ChBr), choline iodide (ChI), and methyl urea based DESs show that the DES composed of ChCl and methyl urea has the largest potential window. This work may aid the selection of ILs or DESs for use as a direct electrolyte or a solvent in electrochemical applications.     

The Role of Hydrogen Bond Donor on the Extraction of Phenolic Compounds from Natural Matrices Using Deep Eutectic Systems

Recently, deep eutectic systems (DESs) as extraction techniques for bioactive compounds have surfaced as a greener alternative to common organic solvents. In order to study the effect of these systems on the extraction of phenolic compounds from different natural sources, a comprehensive review of the state of the art was carried out. In a first approach, the addition of water to these systems and its effect on DES physicochemical properties such as polarity, viscosity, and acidity was investigated. This review studied the effect of the hydrogen bond donor (HBD) on the nature of the extracted phenolics. The effects of the nature of the HBD, namely carbon chain length as well as the number of hydroxyl, methyl, and carbonyl groups, have shown to play a critical role in the extraction of different phenolic compounds. This review highlights the differences between DES systems and systematizes the results published in the literature, so that a more comprehensive evaluation of the systems can be carried out before any experimental trial.     

Theoretical and experimental study of new deep eutectic solvents for extraction of perfluorinated iodoalkanes

There is a lack of attention and reporting in aspects of the neutral/nonionic perfluoroalkyl substances (PFASs) and corresponding treatment mechanisms. Herein, new function-oriented deep eutectic solvents (DESs) with pyridine moiety were designed for perfluorinated iodoalkanes extraction from the oil phase. The effect of hydrogen bond acceptor (HBA) functional groups on the effectiveness of targets retrieval was investigated. Moreover, different structural, quantum-chemical, solvatochromic, and statistical thermodynamics parameters were conducted, calculated, and correlated to the distribution coefficients of the studied DESs. Results showed that functional groups of HBAs significantly affected the extraction effectiveness of eutectic mixtures. The pyridine ring-based DESs with the CO group possessed the highest extraction efficiencies among the studied groups. To some extent, the extraction performances of the DES were substantially affected by the electrostatic potential extrema of the donor halogen atom and pyridine analogues. For targets with relatively short alkyl chain length, the topological indices had a positive relationship with the treatment efficacy of the DESs, and the quantum-chemical parameters of these solvents had a strong negative relationship with them. For targets with long alkyl chain length, the solvatochromic parameters of DES had a great influence on the distribution coefficients and also on the selectivity of these solvents. Furthermore, the halogen and hydrogen bonds presented cooperativity, clarifying via quantum-chemistry calculations. The synergism mechanism between them is beneficial to the extraction of perfluorinated iodoalkanes. Besides shedding light on the structure–property-performance relationships of the DESs, these findings also provided novel insights into the directional design and selection of DESs.     

Preconcentration and Determination of Chlorophenols in Wastewater with Dispersive Liquid–Liquid Microextraction Using Hydrophobic Deep Eutectic Solvents

Abstract

Hydrophobic deep eutectic solvents (DESs) were synthesized and developed for the preconcentration of three chlorophenols from wastewater by dispersive liquid–liquid microextraction (DLLME). The analyte concentrations were determined by high-performance liquid chromatography (HPLC). The hydrophobic DESs were prepared with the combination of hydrogen bond donors of decanoic acid or octanoic acid with different hydrogen bond acceptors of quaternary ammonium salts of tetrabutylammonium chloride, tetraoctylammonium chloride, methyltrioctylammonium chloride, and tetraheptylammonium chloride). Following the study of the stability and characterization by Fourier transform infrared spectroscopy, the hydrophobic DESs were developed as extractants and employed for the removal of 4-chlorophenol (4-CP), 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP) from wastewater. Using hydrophobic DESs as the microextraction solvents, several key parameters were optimized, including the type and volume of the hydrophobic DES, pH, and time of the extraction procedure. Under the optimized conditions, good recoveries from 90.8% to 93.0% were obtained for the three chlorophenols. The limits of detection were less than 0.05?µg/mL with relative standard deviations between 1.8% and 3.1%. The method was applied for the isolation and determination of synthetic chlorophenols in wastewater.     

Application of deep eutectic solvents for the extraction of phenolic compounds from extra-virgin olive oil

A HPLC–DAD/ESI–MS method has been developed and validated for the analysis of the most representative phenolic compounds in extra-virgin olive oil (EVOO) samples using a green extraction approach based on deep eutectic solvents (DESs) at room temperature. We examined ten DESs based on choline chloride and betaine in combination with different hydrogen bond donors comprising six alcohols, two organic acids, and one urea. Five phenolic compounds, belonging to the classes of secoiridoids and phenolic alcohols, were selected for the evaluation of extraction efficiency. A betaine-based DES with glycerol (molar ratio 1:2) was found to be the most effective for extracting phenolic compounds as compared to a conventional solvent. The optimization of the extraction method involved the study of the quantity of water to be added to the DES and evaluation of the sample-to-solvent ratio optimal condition. Thirty percent of water added to DES and sample to solvent ratio 1:1 (w/v) were selected as the best conditions. The chromatographic method was validated by studying LOD, LOQ, intraday and interday retention time precision, and linearity range. Recovery values obtained spiking seed oil sample aliquots with standard compounds at 5 and 100 μg/g concentration were in the range between 75.2% and 98.7%.     

Molecularly Imprinted Polymers Modified by Deep Eutectic Solvents and Ionic Liquids with Two Templates for the Simultaneous Solid-Phase Extraction of Fucoidan and Laminarin from Marine Kelp

Molecularly imprinted polymers modified by deep eutectic solvents and ionic liquids (ILs) were prepared as packing materials for the solid-phase extraction (SPE) of fucoidan and laminarin. The prepared materials were characterized by field emission scanning electron microscopy and Fourier transform infrared spectroscopy. The polymers modified by the deep eutectic solvent prepared by choline chloride and urea had the best extraction efficiencies for fucoidan and laminarin (95.5% and 87.6%, respectively) from marine kelp. The relative standard deviations for intraday and interday determination were less than 4.23%. The molecularly imprinted polymers modified by deep eutectic solvents and ILs showed outstanding applications for SPE and may offer novel sample pretreatment for other analytes.