ELECTROCHEMISTRY
·
2023
·Vol. 91
·期 8
·087003-087003
·
IF 2.5
Fenghai LIU,Jiasheng SONG,Wenxiu SHI,Shengnan LI,Guiming LIU,Tong LI,Shengzhong RONG,Yingying NIU,Xiaowei YANG,Hongzhi PAN
In this paper, an ionic liquid (IL) was dripped onto a reduced graphene oxide (R-GO) and composite-modified glassy carbon electrode (GCE) used as an electrochemical sensor. The sensor was used to detect the lead and cadmium ions codeposited with bismuth ions in rice by differential pulse voltammetry. The method exhibited good linearity and perfect applicability. The developed sensor was used to determine the contents of lead and cadmium in rice, and the results were compared with those of the certified method; there was no significant difference between the developed sensor and the certified method at the 95 % confidence level, so the method could be applied in practice.
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GREEN CHEMISTRY
·
2021
·Vol. 23
·期 24
·9922-9934
·
IF 10.182
Yuqing Shen,Chaoping Yuan,Xianyi Zhu,Qin Chen,Shenjun Lu,Haibo Xie
The facile design and preparation of polyelectrolytes is a frontier topic in the fields of polymer science, energy storage devices and catalysis. Herein, linear water soluble cellulosic poly(protic ionic liquid) (CPIL) electrolytes were facilely and atom economically prepared after the dissolution of cellulose in the newly developed DBU/CO2/DMSO solvent system, followed by the simple addition of succinic anhydride under mild conditions. The DBU not only participated in the dissolution of cellulose as a solvent component, but also acted as an organocatalyst for the acylation reaction of cellulose with succinic anhydride, as well as a cation component in the targeted CPIL electrolytes. The reaction was optimized, and the effect of the reaction conditions on the chemical and physical properties of the CPILs was investigated. And then, as a proof of concept, the CPIL electrolyte aqueous solution was successfully used as the catalytic reaction media for the Knoevenagel condensation reaction. It was found that the reaction was homogeneous at the beginning, and the products could precipitate out from the media with the proceeding of the reaction, thus affording satisfactory filtration yields ranging from 56.7% to 93.8%. The solution properties of the CPIL aqueous solution were primarily investigated towards an in-depth understanding of the catalytic mechanism, by which a synergetic catalytic mechanism of the CPILs was proposed, and the reaction started with a nucleophilic addition reaction, and was then followed by a fast dehydration reaction. Finally, the direct reusability potential of the CPIL aqueous solution after the product filtration was also primarily investigated for the Knoevenagel condensation reaction.
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Molecular Catalysis
·
2021
·
IF 5.062
Zhong-Qiu Liu,Sheng-Nan Li,Qing-Shuai Zeng,Yu-Jing Liu,Jin-Mao You,An-Guo Ying
The preparation of mesoporous poly(ionic liquid)s (MPILs) is critically fundamental for the design of heterogeneous catalysts, whereas traditional methods are difficult to obtain these materials with both well-defined mesoporous structure and unique functionality. Here, HClO 4 -functionalized MPILs with well-defined mesoporous structure were successfully fabricated, in which the alkene-modified Fe 3 O 4 nanoparticles as structural reinforcer play a vital role for mesoporous structure formation. The MPILs were characterized by N 2 adsorption/desorption, scanning electron microscope (SEM), transmission Electron Microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and vibration sample magnetometry (VSM), and the results confirm that MPILs possess moderate surface area, well-defined mesoporosity, abundant active ionic centers, as well as efficient magnetic recovery. The resulting MPILs show excellent catalytic activity for condensation reaction and Knoevenagel condensation. The kinetic study reveals that the excellent catalytic activity of MPILs is attributed to the synergistic catalysis of mesoporous confinement effect and hydrogen proton from MPILs, albeit with mass transfer resistance produced by mesoporous channels. Further, the catalyst can be recovered using an external magnetic field and reused at least 10 times without a considerable decrease in its catalytic activity. Finally, alkene-modified Fe 3 O 4 nanoparticle-mediated mesoporous construction promotes a textural engineering approach to the development of novel mesoporous materials for other applications.
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EUROPEAN FOOD RESEARCH AND TECHNOLOGY
·
2021
·Vol. 247
·期 11
·2777-2785
·
IF 2.998
Yang Yi,Yin Shuo,Wu Ling,Li Yongxin,Sun Chengjun
A novel ionic liquid-based air-assisted dispersive liquid–liquid microextraction combined with high-performance liquid chromatographic method was developed for the simultaneous analysis of oxytetracycline, tetracycline, demeclocycline, metacycline, chlortetracycline and doxycycline in honey. Tetracyclines in samples were extracted with ethyl acetate-[Bmim]PF 6 under acidic condition with the assistance of air. The analytes were separated on a C 18 column thermostated at 20 °C under gradient condition with a mobile phase consisted of methanol and oxalic acid. Parameters for the extraction (pH, dilution buffer, ionic strength, volumes of ionic liquid and ethyl acetate, assistance techniques and extraction time) were evaluated. The developed method showed good linearities over the range of 10.0–500 μg/L ( R 2 > 0.999). The enrichment factors were 16.6–41.2. The detection limits and quantification limits were 0.434–0.919 μg/kg and 1.45–3.06 μg/kg, respectively. The recoveries were 89.5–116%. The intra-day and inter-day RSDs were 0.644–6.44% and 2.35–15.9%, respectively. The developed method is sensitive, accurate, rapid, convenient, and is applicable for the determination of six tetracyclines in honey.
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GREEN CHEMISTRY
·
2021
·Vol. 23
·期 21
·8571-8580
·
IF 10.182
Yuting He,Huimin Lu,Xue Li,Jun Wu,Tiancheng Pu,Wei Du,Hongping Li,Jing Ding,Hui Wan,Guofeng Guan
The multi-step reaction of CO2 over basic catalysts significantly improves the diversity of products, vividly embodying the ability of green chemistry to turn waste into treasure. However, under a Lewis acidic CO2 atmosphere, the activity maintenance of the multi-step reaction puts forward higher requirements for the reversible regeneration ability of the basic catalysts. Novel Lewis–Brønsted binary basic poly(ionic liquid)s (LB-PILs) were successfully developed through a radical copolymerization followed by ion-exchange strategy, and were applied to the two-step synthesis of dimethyl carbonate (DMC) by coupling CO2 cycloaddition and CH3OH transesterification without any cocatalyst. Relying on the activation of CO2 by Lewis basic tertiary N and the thermal recovery of nucleophilic HCO3− to stronger Brønsted basic OH− with the help of temperature control in CH3OH transesterification, the LB-PILs presented high activity, stable repeatability and linear carbonate universality. In situ IR analysis and Knoevenagel condensation, combined with theoretical calculations, provided reliable support for the ingenious incorporation of reversible regeneration of basic catalysts in a Lewis acidic CO2 atmosphere and multi-step coupling reaction process of CO2.
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JOURNAL OF MOLECULAR LIQUIDS
·
2019
·
IF 4.561
Han Jia,Pan Huang,Qiuxia Wang,Yugui Han,Shaoyan Wang,Jiajun Dai,Jinyong Song,Fan Zhang,Hui Yan,Kaihe Lv
It is an urgent subject to search high-performance shale inhibitors used in water-based drilling fluids for drilling safety. In the present work, two imidazolium-based ionic liquids (ILs), 1-hexyl −3-methylimidazolium bromide (BMH) and its corresponding gemini type, 1,2-bis(3-hexylimidazolium-1-yl) ethane bromide (HMH), were introduced as promising shale inhibitors. The inhibition performances were assessed and compared with the conventional inhibitors potassium chloride and polyether diamine (PDA) via the inhibition evaluation tests including sodium bentonite (Na-bent) pellets immersing tests, linear swelling tests and shale hot-rolling recovery tests. Both ILs inhibitors, especially HMH, shown terrific inhibition performance with lower dosages and maintained high-performance at temperature up to 160 °C. The inhibition mechanism was analyzed by FTIR , X-ray diffraction (XRD), Zeta potential tests, particle size distribution measurement, contact angle measurement and surface tension measurement. The results demonstrated both BMH and HMH effectively inhibit the shale hydration and swelling. HMH, with two positively charged headgroups and two hydrophobic tails, was better than BMH in entering the interlayer space of clay, reducing Zeta potential, forming hydrophobic shield and reducing the surface tension, which was responsible for its superior inhibition performance.
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CHROMATOGRAPHIA
·
2018
·Vol. 81
·期 10
·1391-1400
·
IF 1.401
Pang Xiaomin,Bai Ligai,Lan Dandan,Guo Bin,Wang Huimin,Liu Haiyan,Ma Zhengyue
An 1-vinyl-3-hexyl imidazolium bromide ionic liquid-based monolithic column was prepared via in situ free radical polymerization, which was used as the sorbent of on-line solid phase extraction. The prepared material was characterized by scanning electron microscopy, nitrogen adsorption–desorption instrument and mercury intrusion porosimetry, respectively, and the results showed that the homemade monolith occupied relatively uniform porous structure and high-specific surface area of 212.53 m 2 g −1 . On-line solid phase extraction–high-performance liquid chromatography was performed to quantitatively analyze five steroid drugs, including betamethasone, norgestrel, halcinonide, beclomethasone dipropionate and testosterone propionate in human plasma. The determination procedure was carried out following the optimization of the mobile phase composition. Methodological validation showed that correlation coefficients of the linear regressions were in the range of 0.9989–0.9992; the values of relative standard deviation for precision were in the range of 1.39–6.15% for intra-day and 0.32–6.34% for inter-day, respectively; the values of accuracy expressed by recovery were in the range of 99.02–101.98, 93.27–102.89, 102.79–104.01, 100.04–102.61 and 100.77–102.44% for the five drugs in order, respectively; the values of relative standard deviation for repeatability calculated according to retention times and peak areas of the five drugs were in the ranges of 0.28–0.76% ( n = 5) and 0.84–2.63% ( n = 5), respectively. The results showed that the polymer monolithic column was feasible for an on-line solid phase extraction column, exhibiting good selectivity and high permeability.
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JOURNAL OF SEPARATION SCIENCE
·
2014
·Vol. 37
·期 8
·1004-1011
·
IF 2.594
Longhui Liu,Lijun He,Xiuming Jiang,Wenjie Zhao,Guoqiang Xiang,Jared L. Anderson
In this study, silica modified with a 30-membered macrocyclic polyamine was synthesized and first used as an adsorbent material in SPE. The SPE was further combined with ionic liquid (IL) dispersive liquid–liquid microextraction (DLLME). Five polycyclic aromatic hydrocarbons were employed as model analytes to evaluate the extraction procedure and were determined by HPLC combined with UV/Vis detection. Acetone was used as the elution solvent in SPE as well as the dispersive solvent in DLLME. The enrichment of analytes was achieved using the 1,3-dibutylimidazolium bis[(trifluoromethyl)sulfonyl]imide IL/acetone/water system. Experimental conditions for the overall macrocycle-SPE–IL-DLLME method, such as the amount of adsorbent, sample solution volume, sample solution pH, type of elution solvent as well as addition of salt, were studied and optimized. The developed method could be successfully applied to the analysis of four real water samples. The macrocyclic polyamine offered higher extraction efficiency for analytes compared with commercially available C 18 cartridge, and the developed method provided higher enrichment factors (2768–5409) for model analytes compared with the single DLLME. Good linearity with the correlation coefficients ranging from 0.9983 to 0.9999 and LODs as low as 0.002 μg/L were obtained in the proposed method.
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ANALYTICA CHIMICA ACTA
·
2014
·
IF 4.517
Mian Wu,Haibo Zhang,Faqiong Zhao,Baizhao Zeng
A novel poly(3,4-ethylenedioxythiophene)-ionic liquid (i.e., 1-hydroxyethyl-3-methyl imidazolium-bis[(trifluoromethyl)sulfonyl]imide) composite film was electrodeposited on a Pt wire for headspace solid-phase microextraction. The film showed nodular structure and had large specific surface. In addition, it displayed high thermal stability (up to 300 °C) and durable property (could be used for more than 200 times). Coupled with gas chromatography-flame ionization detection, the resulting fiber was applied to the headspace solid-phase microextraction and determination of several alcohols (i.e., linalool, nonanol, terpineol, geraniol, decanol and dodecanol). It presented higher extraction capability in comparison with the poly(3,4-ethylenedioxythiophene) and commercial polydimethylsiloxane/divinylbenzene fiber. Under the optimized conditions, the linear ranges exceeded three magnitudes with correlation coefficients above 0.9952 and the low limits of detection were 34.2–81.3 ng L −1 . For different alcohols the repeatabilities (defined as RSD) were <5.8% and <7.8% for single fiber ( n = 5) and fiber-to-fiber ( n = 4), respectively. The proposed method was applied to the determination of these alcohols in real samples with acceptable recoveries from 81.1% to 106.6%.
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ELECTROPHORESIS
·
2015
·Vol. 36
·期 20
·2530-2537
·
IF 3.028
Teng Ma,Zheng Li,Qian Niu,Yuanyuan Li,Weihong Zhou
In this work, double dispersant-assisted ionic liquid dispersive liquid–liquid microextraction coupled with micellar electrokinetic chromatography was developed to determine four UV filters (benzophenone, 4-hydroxybenzophenone, 2,4-dihydroxybenzophenone, and 2-hydroxy-4-methoxybenzophenone). 1-Hexyl-3-methylimidazolium hexafluorophosphate was used as the extraction solvent. The main novelty of the present work was that acetonitrile-Triton X-114 was used as double disperser solvent. Parameters affected the extraction efficiency were investigated and optimized. Under the optimum conditions, enrichment factors were in the range of 25.3−40.5. The limits of detection and quantitation, calculated at a S/N of three and ten, were 3.9−6.7 ng/mL and 13.0−22.3 ng/mL. The linearity of the method was in the range of 0.02−2 μg/mL for 2, 4-dihydroxybenzophenone and 4-hydroxybenzophenone, 0.01−2 μg/mL for benzophenone and 2-hydroxy-4-methoxybenzophenone, with correlation coefficient ( R 2 ) of 0.9984−0.9991. The proposed method was successfully applied to the determination of four benzophenone-type UV filters in six kinds of sunscreen cosmetic products, with yielded relative recoveries ranging from 80.2 to 117.7%.
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Food Analytical Methods
·
2013
·Vol. 7
·期 2
·291-297
·
IF 1.969
Wen Shengping,Zhu Xiashi
A simple and rapid method based on dispersive liquid–liquid microextraction with room temperature ionic liquid 1,3-dibutylimidazolium hexafluorophosophate ([BBIM][PF 6 ]) coupled to flame atomic absorption spectrometry was developed for the speciation of Mn(II)/Mn(VII) in tea samples. The main factors affecting dispersive liquid–liquid microextraction were investigated in detail. Mn(II) and total manganese [Mn(II)+Mn(VII)] were quantitatively extracted after adjusting aqueous sample solution to pH 10.0 and 7.0, respectively. Mn(VII) was calculated by subtraction of Mn(II) from total manganese. Under the optimized conditions, the limits of detection (3 σ ) for Mn(II) and Mn(VII) were 0.26 and 1.86 ng/mL, and their relative standard deviations were 2.6 and 4.8 % ( n = 7, c = 25.00 ng/mL). The proposed method was validated by the determination of Mn(II) and Mn(VII) in the certified reference material [GBW(E)08513] of tea sample and different local tea samples with satisfactory results.
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JOURNAL OF CHROMATOGRAPHY A
·
2015
·
IF 4.169
Meseret Amde,Zhi-Qiang Tan,Rui Liu,Jing-Fu Liu
Using a nanofluid obtained by dispersing ZnO nanoparticles (ZnO NPs) in 1-hexyl-3-methylimidazolium hexafluorophosphate, new single drop microextraction method was developed for simultaneous extraction of three fungicides (chlorothalonil, kresoxim-methyl and famoxadone) in water samples prior to their analysis by high performance liquid chromatography (HPLC-VWD). The parameters affecting the extraction efficiency such as amount of ZnO NPs in the nanofluid, solvent volume, extraction time, stirring rate, pH and ionic strength of the sample solution were optimized. Under the optimized conditions, the limits of detection were in the range of 0.13–0.19 ng/mL, the precision of the method assessed with intra-day and inter-day relative standard deviations were <4.82% and <7.04%, respectively. The proposed method was successfully applied to determine the three fungicides in real water samples including lake water, river water, as well as effluent and influent of wastewater treatment plant, with recoveries in the range of 74.94–96.11% at 5 ng/mL spiking level. Besides to being environmental friendly, the high enrichment factor and the data quality obtained with the proposed method demonstrated its potential for application in multi residue analysis of fungicides in actual water samples.
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