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Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are high nutritional components. Evidence for unique effects of them is increasing. Further understanding of their independent biological functions urgently needs more efficient separation techniques. Nowadays, most of the commercially available fish oil products are the mixture of eicosapentaenoic acid ethyl ester (EPAEE) and docosahexaenoic acid ethyl ester (DHAEE). It will be convenient to directly separate esterified EPA and DHA without saponification pretreatment. However, it is of great challenge to separate EPAEE and DHAEE because of their extremely fat-soluble nature and the equivalent chain length rule. In this research, the suitability of green guanidinium ionic liquid (IL) in countercurrent chromatography (CCC) solvent system for the separation of them was evaluated for the first time. Compared with imidazolium IL and phosphonium IL, guanidinium IL based non-aqueous biphasic system showed more outstanding separation performance. The separation mechanism was elucidated in depth through quantum mechanical calculations. It was found that guanidinium IL acted a crucial role in the CCC separation, which resulted in difference of partition behavior of EPAEE and DHAEE via different hydrogen-bonding affinity. EPAEE and DHAEE were successfully separated by solvent system (n-heptane/methanol/propylguanidinium chloride ([C 3 Gun]Cl, 1:1:5%, v/v/m)) with high purity (>95%) in one step, which was not achieved beforehand. Moreover, an easy recycling procedure of IL had also been devised, which significantly reduced waste generated. It opens up a new way for reasonable design water-free two-phase solvent system for efficient separation of very non-polar lipid compounds., Competing Interests: Declaration of Competing Interests The authors declare that they have no conflict of interest., (Copyright © 2020. Published by Elsevier B.V.)

Tocopherol homologues are important fat-soluble bioactive compounds with high nutritional value. However, it is of great challenge to separate these homologues because of their high structural similarities. In this work, ionic-liquid-based countercurrent chromatography was used for the separation and purification of tocopherol homologues. Conventional countercurrent chromatography and ionic-liquid-based countercurrent chromatography solvent systems were evaluated in respect of partition coefficient, separation factor, and stationary phase retention factor to separate these targets. Kind of ionic liquids, amount of ionic liquid, and sample amount were systematically optimized. A novel countercurrent chromatography non-aqueous biphasic system composed of n-hexane-methanol-1-butyl-3-methylimidazolium chloride was established. The baseline separation of tocopherol mixtures was obtained in one cycle process. The ionic liquid played a key role in the countercurrent chromatography separation, which resulted in difference of partition behavior of individual tocopherol in the whole system through different hydrogen-bonding affinity. Finally, n-hexane-methanol-1-butyl-3-methylimidazolium chloride (5:5:3, v/v) water-free biphasic system was successfully applied to separate tocopherol homologues from vegetable oil that was not achieved beforehand. This method can be widely employed to separate many similar molecules such as tocotrienols, tocomonoenols, and marine-derived tocopherol in food samples., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

To elucidate the relationship between the structure of ionic liquid (IL) and its enrichment ability to trace pesticides from an environmental water sample, a series of imidazole-based ILs were synthesized to extract four fungicides (boscalid, cyprodinil, fluazinam, and pyrimethanil) through an in situ ionic liquid dispersive liquid-liquid microextraction method. The results showed that aromatic heterocyclic monocation ionic liquids (MILs) had better extraction ability to fungicides than other three alicyclic heterocyclic MILs. Dication ionic liquids (DILs) with the four carbons at the side chain had better ability to extract fungicides than MILs, and DILs with a long bridge carbon chain had better recoveries of fungicides with low K ow values. The proposed method showed high mean enrichment factors and high recoveries of the fungicides from real water samples. The rules of the relationship between the structure of IL and enrichment ability are instructive to the application of ILs in pretreatment of complex substances.

As a widely used herbicide, picloram has been frequently detected in the aquatic environment due to its high leaching potential and low adsorption by soil. To reduce aquatic environmental risk of this herbicide caused by leaching and runoff, five herbicidal ionic liquids (HILs) based on picloram were prepared by pairing isopropylamine, octylamine, octadecylamine, 1-methylimidazole, 4-methylmorpholine respectively. Their physicochemical properties including water solubility, octanol-water partition coefficient, surface activity, leaching, as well as soil adsorption were compared. The results showed that these properties could be adjusted by appropriate selection of counter cations. The HILs with long alkyl chains in cations had low water solubility and leaching characteristics, good surface tension and lipophilicity, as well as high soil adsorption. Compared with currently used picloram in the forms of potassium salts, HIL3 had more excellent herbicidal activity against broadleaf weeds and may offer a lower use dosage. The HILs based on picloram can reduce its negative effects on the aquatic environment and can be used as a desirable alternative to commercial herbicidal formulations of picloram in future., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Delphinidin‐3‐rutinoside, a high‐value of anthocyanin, was isolated and purified by ionic liquid (IL)‐modified countercurrent chromatography (CCC) from waste peel of eggplant (Solanum melongena), one of the most common vegetables consumed all around the world. Different conventional CCC and IL‐CCC solvent systems were evaluated in respect of partition coefficient (K), separation factor (α), and stationary phase retention factor (Sf) to separate polar target and other components. Basic solvent system, kind of ILs, and amount of ILs were systematically optimized by totally K‐targeted strategy, which drastically reduced the experimental effort. Finally, a novel CCC two‐phase solvent system (methyl tert‐butyl ether–butanol–acetonitrile–1% trifluoroacetic acid water–1‐butyl‐3‐methylimidazolium hexafluorophosphate ([C4MIM][PF6]) [2:4:1:5:0.2; v/v/v/v/v]) was successfully established and applied. The baseline separation of target fraction was obtained in one cycle process. The purity of delphinidin‐3‐rutinoside was over 99%. Moreover, the distribution behavior of different kinds of ILs in biphasic solvent system and the removal method of ILs were explored. The results showed that hydrophobic IL significantly improved the partition of polar anthocyanin in organic solvent system, thereby the separation resolution and stationary phase retention through introducing intermolecular forces. This IL‐modified CCC strategy may be applied for the separation of other anthocyanins from variety of natural food resources and waste. [ABSTRACT FROM AUTHOR]

Abstract Cyhalothrin is lethally toxic to aquatic organisms and has caused adverse effects in the hydrosphere. It is urgent to develop efficient and sustainable material for its removal. High-quality HKUST-1 was rapidly synthesized by cholinium ionic liquids (ILs) in water at room temperature. Yields of HKUST-1 showed obviously positive correlation with Hammett values of ILs. When applying CuCl 2 as a copper salt, the yield of products was reached up to 95.5%, which was much higher than that of reported research. The reaction could be readily scalable with high space-time yield (242512 kg m−3 d−1). Additionally, ZrO 2 @HKUST-1 composite was successfully synthesized through a sol-gel method without complicated heat treatment. The whole process eliminates the use of environmentally unfriendly solvents/amines and enables the production of material at a reasonable cost. The obtained HKUST-1 and ZrO 2 @HKUST-1 possessed large pore volume (0.88–0.95 cm3 g−1) and high surface area (1152–1484 m2 g−1). The composite material was used for the adsorption/degradation of cyhalothrin and showed superior photocatalytic activity under moderate visible light, as compared to pure ZrO 2 , HKUST-1 and commercial TiO 2 samples. ZrO 2 @HKUST-1 displayed the high cyhalothrin adsorption capacity of 333 mg g−1 through π−π stacking, which facilitated more target molecules to contact the composite in a short time. ZrO 2 incorporating with HKUST-1 protected ZrO 2 nanoparticles from rapid agglomeration, thus narrowed the band gap of the composite. Moreover, the formation of a junction between HKUST-1 and ZrO 2 effectively reduced the recombination of photoinduced carriers in composite. Therefore, the novel ZrO 2 @HKUST-1 composite can be used as a sustainable efficient heterogeneous photocatalyst for the removal of organic pollutant. Graphical abstract Image 1 Highlights • High-quality HKUST-1 was rapidly synthesized by cholinium ionic liquids in water without heat treatment. • ZrO 2 @HKUST-1 was used for adsorption/degradation of cyhalothrin and showed excellent visible-light photocatalytic activity. • The superior performance of obtained samples was attributed to the outstanding structural properties. • It can be acted as an efficient sustainable heterogeneous photocatalyst for the removal of organic pollutant. [ABSTRACT FROM AUTHOR]

Abstract Auxin herbicides have attracted continuously increasing attention because of their frequently application worldwide, slow degradation rates and potential toxicity to human beings. It is urgent to develop a fast and practical method to monitor them in environmental samples. Ionic liquids (ILs) are not intrinsically "green" and most of them are as toxic as other solvents. Therefore, tuning for maximizing advantageous properties of ILs and minimizing side effects are crucial steps. In this work, guanidinium IL was applied to preconcentrate and clean up ultra-trace auxin herbicides via designable binding sites. The structurally optimized IL had improved pretreatment performance and was significantly less cytotoxic than imidazolium IL toward human keratinocytes. For further improving the sensitivity of detection, we quantified the concentration of herbicides by a fast and mild fluorescence derivatization. Under optimized pretreatment conditions, high recoveries in real water samples (above 80%), short pretreatment time (<3 min for microextraction; 8 min for derivatization) and extremely low limit of detection values (3.90–12.40 ng L−1) were achieved. The proposed method was successfully applied to the analysis of real water samples. Graphical abstract Unlabelled Image Highlights • Guanidinium IL-based in-situ DLLME method was developed for the detection of auxin herbicides in water samples. • The structurally optimized guanidinium IL showed an increase in microextraction performance with lower cytotoxicity. • This method reduced the utilization of hazardous solvents, had short time and applied energy-efficient devices. • This study shows the feasibility of tailoring specific IL as greener solvent in the -analysis of environmental pollutants. [ABSTRACT FROM AUTHOR]

The massive release of rhodamine B (RhB) to water system is an emerging problem, which dramatically threaten environment and human health. The development of an adsorbent with enhanced removal efficiency for RhB is urgently needed. Herein, we report an environment-friendly synthesis of high quality zeolitic imidazolate framework-8 (ZIF-8) and functional ionic liquid@ZIF-8 in water-based system without heat treatment for improving its adsorption property. Guanidinium ionic liquids (ILs) could not only act as greener agents instead of volatile bases and toxic surfactants to efficiently control the nucleation and growth rate of ZIF-8, but also were incorporated as shell material to add specific adsorption sites. The relationship between nanoparticle structure and adsorption performance for RhB was systematically investigated. Due to high surface area (1167 m 2  g −1 ), high porosity (0.79 cm 3  g −1 ), high crystallinity, nano size (about 100 nm) and monodispersity, the as-obtained ZIF-8 showed improved adsorption capacity toward RhB (80% removal efficiency). Heteropolyanion-based guanidinium IL@meso-ZIF-8 (HPAIL@meso-ZIF-8) exhibited the high RhB uptake capacity of 278 mg g −1 (higher than most of the reported adsorbents) and effectively removed 99% of RhB within 15 min. The results showed that the adsorption process of prepared materials fitted well with pseudo-second-order kinetics and Langmuir isotherm model. The existence of mesopores in ZIF-8 facilitated the diffusion of RhB and the incorporated guanidinium IL played a significant role in enhancing the adsorption affinity. Moreover, the reusability results revealed the HPAIL@meso-ZIF-8 as a highly efficient adsorbent for RhB removal with satisfactory performance and structural stability. Therefore, HPAIL@meso-ZIF-8 is one of the most promising adsorbents for organic dye removal from water. [ABSTRACT FROM AUTHOR]

Many herbicides exhibit some disadvantages such as high water solubility and volatility after application, which lead to potential threats to the aquatic and atmospheric environment and human health. Herbicidal ionic liquids (HILs) can effectively eliminate these intrinsic shortcomings by pairing with appropriate counterions (cation or anion). In this study, new HILs based on bromoxynil with eight typical cations were synthesized to reduce the negative impacts of currently used forms of bromoxynil. All the obtained compounds were investigated for solubility, octanol–water partition coefficient, surface activity, volatilization rate, and herbicidal activity in a greenhouse. The results showed that the HILs with long alkyl chains in the cations had reduced water solubility and volatilization rate, better surface activity and Kow, and substantially improved efficacy against weeds over bromoxynil sodium. Due to their adjustable physicochemical properties and improved herbicidal activity, the HILs could tremendously reduce the adverse impacts of bromoxynil on the environment and human health and may be potential alternatives to currently popular forms of bromoxynil in the future. [ABSTRACT FROM AUTHOR]

In this work, in-situ ionic liquid dispersive liquid-liquid microextraction combined ultrasmall Fe 3 O 4 magnetic nanoparticles was developed as a kind of pretreatment method to detect pyrethroid pesticides in water samples. New anion-exchange reagents including Na[DDTC] and Na[N(CN) 2 ] were optimized for in-situ extraction pyrethroids, which showed enhanced microextraction performance. Pyrethroids were enriched by hydrophilic ionic liquid [P 4448 ][Br] (aqueous solution, 200 μL, 0.2 mmol mL −1 ) reaction in-situ with anion-exchange reagent Na[N(CN) 2 ] (aqueous solution, 300 μL, 0.2 mmol mL −1 ) forming hydrophobic ionic liquid as extraction agent in water sample (10 mL). Ultrasmall superparamagnetic iron oxide nanoparticles (30 mg) were used to collect the mixture of ionic liquid and pyrethroids followed by elution with acetonitrile. The extraction of ionic liquid strategies was unique and efficiently fulfilled with high enrichment factors (176–213) and good recoveries (80.20–117.31%). The method was successively applied to the determination of pyrethroid pesticides in different kinds of water samples with the limits of detection ranged from 0.16 to 0.21 μg L −1 . The proposed method is actually nanometer-level microextraction (average size 80 nm) with the advantages of simplicity, rapidity, and sensitivity. [ABSTRACT FROM AUTHOR]

Alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA) are some of the main Alternaria mycotoxins that can be found as contaminants in food materials. The objective of this study was to develop a pretreatment method with countercurrent chromatography (CCC) for enrichment and cleanup of trace Alternaria mycotoxins in food samples prior to high-performance liquid chromatography (HPLC) analysis. An Analytical CCC instrument with a column volume 22.5 mL was used, and a two-phase solvent system composed of ethyl acetate and water modified with 6% [HOOMIM][Cl] in mass to volume ratio was selected. Under the optimized CCC operation conditions, trace amounts of AOH, AME, and TeA in large volume of liquid sample were efficiently extracted and enriched in the stationary phase, and then eluted out just by reversing the stationary phase as mobile phase in the opposite flowing direction tail-to-head. The enrichment and elution strategies are unique and can be fulfilled online with high enrichment factors (87–114) and high recoveries (81.14–110.94%). The method has been successively applied to the determination of Alternaria mycotoxins in real apple juice and wine samples with the limits of detection (LOD) in the range of 0.03–0.14 μg L −1 . Totally 12 wine samples and 15 apple juice samples from the local market were analyzed. The detection rate of AOH and AME in both kinds of the samples were more than 50%, while TeA was found in relatively high level of 1.75–49.61 μg L −1 in some of the apple juice samples. The proposed method is simple, rapid, and sensitive and could also be used for the analysis and monitoring of Alternaria mycotoxin in other food samples. [ABSTRACT FROM AUTHOR]

A countercurrent chromatography method for the enrichment and cleanup of chlorophenols from food samples was successfully established by using an ionic-liquid-modified two-phase solvent system composed of dichloromethane containing 2% 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and water. The column was firstly filled with the organic stationary phase, and then a large volume of sample was pumped into the column after it was equilibrated with pure water at the rotation speed. Finally, the trace amounts of chlorophenols extracted and enriched in the stationary phase were eluted out by an alkaline mobile phase and determined by high-performance liquid chromatography. Under optimized conditions, the enrichment and cleanup of the chlorophenols can be fulfilled online with enrichment factors (34-65) and high recoveries (84.69-95.23%). The method has been applied to the determination of chlorophenols in real red wine samples with the limits of detection in the range of 1.89-4.21 μg/L. The present method is highly suitable for the pretreatment of large volume of aqueous sample for the determination of trace amounts of contaminants in food and environmental samples. [ABSTRACT FROM AUTHOR]

In-situ ionic liquid-dispersive liquid–liquid microextraction (IL-DLLME) method was developed as a pretreatment method for the detection of six chlorophenols (CPs) in honey samples. The hydrophobic ionic liquid [C 4 MIM][NTf 2 ], formed in-situ by the hydrophilic ionic liquid [C 4 MIM][BF 4 ] and the ion exchange reagent LiNTf 2 was used as the microextractant solvent of CPs from honey sample. Then the enriched analytes were back-extracted into 40 μL of 0.14 M NaOH solution and finally subjected to analysis by high-performance liquid chromatography. The method showed low limit of detection of CPs, 0.8–3.2 μg/L and high enrichment factor, 34–65 with the recoveries range from 91.60% to 114.33%. The method is simple, rapid, environmentally friendly and with high extraction efficiency. [ABSTRACT FROM AUTHOR]