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  • [Wiley数据库][2012]Electrodeposited Graphene and Silver Nanoparticles Modified Electrode for Direct Electrochemistry and Electrocatalysis of Hemoglobin
  • 更新时间:2016-03-15;信息类型:期刊文章
  • By using a 1-butylpyridinium hexafluorophosphate based carbon ionic liquid electrode (CILE) as the working electrode, graphene (GR) nanosheets and silver nanoparticles (Ag NPs) were step by step electrodeposited on the surface of the CILE with potentiostatic method. The fabricated Ag/GR/CILE was used as a new platform for protein electrochemistry and hemoglobin (Hb) was immobilized on its surface with chitosan (CTS) as film forming material. In 0.1 mol/L phosphate buffer solution, a pair of well-defined and quasi-reversible redox peaks appeared on the CTS/Hb/Ag/GR/CILE with a formal peak potential of -0.202 V (vs. SCE) and a peak-to-peak separation (ΔEp) of 68 mV, which indicated that direct electrochemistry of Hb was realized on the modified electrode. The results could be attributed to the synergistic effects of Ag NPs and GR nanosheets on the electrode surface, which provided a specific three-dimensional structure with high conductivity and good biocompatibility. The Hb modified electrode showed excellent electrocatalysis to the reduction of trichloroacetic acid in the concentration range from 0.8 to 22.0 mmol/L with a detection limit of 0.42 mmol/L (3σ). Moreover, the modified electrode exhibited favorable reproducibility, long term stability and accuracy, with potential applications in the third-generation electrochemical biosensor.
  • 链接地址:http://www.ionike.com/download/c-articles/2016-03-15/335.html
  • [Wiley数据库][2012]Application of NiMoO4 Nanorods for the Direct Electrochemistry and Electrocatalysis of Hemoglobin with Carbon Ionic Liquid Electrode
  • 更新时间:2016-03-15;信息类型:期刊文章
  • In this paper NiMoO4 nanorods were synthesized and used to accelerate the direct electron transfer of hemoglobin (Hb). By using an ionic liquid (IL) 1-butylpyridinium hexafluorophosphate (BPPF6) modified carbon paste electrode (CILE) as the basic electrode, NiMoO4 nanorods and Hb composite biomaterial was further cast on the surface of CILE and fixed by chitosan (CTS) to establish a modified electrode denoted as CTS/NiMoO4-Hb/CILE. UV-vis and FT-IR spectroscopic results showed that Hb in the film retained its native structures without any conformational changes. Electrochemical behaviors of Hb entrapped in the film were carefully investigated by cyclic voltammetry with a pair of well-defined and quasi-reversible redox voltammetric peaks appearing in phosphate buffer solution (PBS, pH 3.0), which was attributed to the direct electrochemistry of the electroactive center of Hb heme Fe(III)/Fe(II). The results were ascribed to the specific characteristic of NiMoO4 nanorods, which accelerated the direct electron transfer rate of Hb with the underlying CILE. The electrochemical parameters of Hb in the composite film were further carefully calculated with the results of the electron transfer number (n) as 1.08, the charge transfer coefficient (a) as 0.39 and the electron-transfer rate constant (ks) as 0.82 s-1. The Hb modified electrode showed good electrocatalytic ability toward the reduction of trichloroacetic acid (TCA) in the concentration range from 0.2 to 26.0 mmol/L with a detection limit of 0.072 mmol/L (3σ), and H2O2 in the concentration range from 0.1 to 426.0 mmol/L with a detection limit of 3.16×10-8 mol/L (3σ).
  • 链接地址:http://www.ionike.com/download/c-articles/2016-03-15/334.html
  • [Wiley数据库][2012]Dehydration of Carbohydrates to 5-Hydroxymethylfurfural in Ionic Liquids Catalyzed by Hexachlorotriphosphazene
  • 更新时间:2016-03-15;信息类型:期刊文章
  • Development of efficient catalysts for the dehydration of carbohydrates to produce 5-hydroxymethylfurfural (HMF) is a very attractive topic. In this work, dehydration of fructose catalyzed by three organic molecules, including hexachlorotriphosphazene (N3P3Cl6), trichloromelamine (C3N6H3Cl3) and N-bromosuccinimide (NBS), was studied in ionic liquids. It was discovered that the three organic molecules had high activity in accelerating the dehydration of fructose and N3P3Cl6 was the most efficient catalyst among them. The effects of amount of catalysts, temperature, solvents, reaction time, and substrate/solvent weight ratio on the reaction were investigated using N3P3Cl6 as the catalyst and 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) as the solvent. It was demonstrated that the N3P3Cl6/[Bmim]Cl catalytic system was very effective for catalyzing the reaction. The yield of HMF could reach 92.8% in 20 min at the optimized conditions and the N3P3Cl6/[Bmim]Cl system could be reused. Further study indicated that the N3P3Cl6/[Bmim]Cl system was also effective for the dehydration of sucrose and inulin and satisfactory yield could be obtained at suitable conditions.
  • 链接地址:http://www.ionike.com/download/c-articles/2016-03-15/333.html
  • [Wiley数据库][2012]Reconstitution of Cellulose and Lignin After [C2mim][OAc] Pretreatment and Its Relation to Enzymatic Hydrolysis
  • 更新时间:2016-02-28;信息类型:期刊文章
  • Although the effects of cellulose crystallinity and lignin content as two major structural features on enzymatic hydrolysis have been extensively studied, debates regarding their effects still exist. In this study, reconstitution of cellulose and lignin after 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) pretreatment was proposed as a new method to study their effects on enzymatic digestibility. Different mechanisms of lignin content for reduction of cellulose hydrolysis were found between the proposed method and the traditional method (mixing of cellulose and lignin). The results indicated that a slight change of the crystallinity of the reconstituted materials may play a minor role in the change of enzyme efficiency. In addition, the present study suggested that the lignin content does not significantly affect the digestibility of cellulose, whereas the conversion of cellulose fibers from the cellulose I to the cellulose II crystal phase plays an important role when an ionic liquid pretreatment of biomass was conducted.
  • 链接地址:http://www.ionike.com/download/c-articles/2016-02-28/332.html
  • [Wiley数据库][2012]Determination of arecoline in areca nut based on filed amplification in capillary electrophoresis coupled with electrochemiluminescence detection
  • 更新时间:2016-02-26;信息类型:期刊文章
  • A sensitive capillary electrophoresis–electrochemiluminescence (CE–ECL) assay with an ionic liquid (IL) was developed for the determination of arecoline in areca nut. The IL, 1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF4), was an effective additive improved not only the separation selectivity but also the detection sensitivity of the analyte. BMImBF4 in the separation electrolyte made the resistance of the separation buffer much lower than that of the sample solution, which resulted in an enhanced field amplified electrokinetic injection CE. ECL intensity of arecoline is about two times higher than that of the analyte with phosphate–IL buffer system. Resolution between arecoline and other unknown compounds in real samples was improved. Under the optimized conditions (ECL detection at 1.2V, 16kV separation voltage, 20mmol/L phosphatewith 10mmol/L BMImBF4 bufferat pH 7.50,5mmol/L Ru(bpy)32+ and 50mmol/Lphosphatebuffer in the detection reservoir), a detection limit of 5 10–9mol/L for arecoline was obtained. Relative standard deviations of the ECL intensity and the migration time were 4.51% and 0.72% for arecoline. This method was successfully applied to determination of the amount of arecoline in areca nut within 450s.
  • 链接地址:http://www.ionike.com/download/c-articles/2016-02-26/331.html
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