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Summary

An efficient ionic liquid-based microwave-assisted (IL-MAE) method has been developed for extraction of dehydrocavidine from Corydalis saxicola Bunting (C. saxicola) for subsequent rapid analysis by high-performance liquid chromatography (HPLC). The yield of dehydrocavidine reached 9.446 mg g−1 within 10 min under the optimum IL-MAE conditions (1.5 mol L−1 [hmim]Br as extraction solvent, liquid-to-solid ratio 20:1 (mL:g), and extraction temperature 70°C). Compared with conventional procedures, the proposed IL-MAE method has many advantages, for example high extraction yield, short extraction time, low solvent consumption, no use of volatile organic solvents, and no further sample clean-up before HPLC analysis. The method was validated for limit of detection (LOD) and quantification (LOQ), linearity, precision, recovery, and reproducibility. The calibration range was 5.0–200 mg L−1 and the correlation coefficient, r, was 0.9996. The LOD and LOQ were 0.035 and 0.12 mg L−1, respectively. The relative standard deviations of intra-day and inter-day assays were below 2.6% and 6.5%, respectively. Recovery was between 93.8% and 109.3% with RSD values below 5.0%. The method can be used for rapid and effective extraction and analysis of active components from medicinal plants.

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Journal of Thermal Analysis and Calorimetry
Authors:
J. Murillo-Hernández
,
S. López-Ramírez
,
J. Domínguez
,
C. Duran-Valencia
,
I. García-Cruz
, and
J. González-Guevara

Abstract  

A survey on the effect of ionic liquids (ILs) over the thermal stability of a heavy Mexican oil was performed. ILs used were based on [Cnim]+ and [Cnpyr]+ organic cations with FeCl4 metal anion. Mixtures of heavy crude oil (HCO) with ILs show three oxidation zones: low temperature oxidation (LTO), full deposition (FD) and high temperature oxidation (HTO). Thermal stability and mass loss decrease in the LTO zone but increase in the FD and HTO zones for every ILs used. The activation energy of the oxidation is influenced by the ILs in the HTO zone. It decreases when increasing the size of the organic radical substitute in the cation of the ILs while it increases with the presence of hydroxyl groups. The influence of electronic structure and reactivity indexes are rationalized to understand the variations of activation energy obtained of the reaction systems. Among all cations used, cation-3 (IL-3) shows the greater value of HOMO-LUMO gap as well as the lower activation energy.

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Introduction Ionic liquids have received considerable attention recently for their wide range of applications, which are invariably possible due to attractive physical and chemical properties of these materials [ 1 – 5 ]. These

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Introduction As green solvents, ionic liquids especially air and water stable ionic liquids have gained great attention [ 1 – 3 ]. In recent decades, the study of ionic liquids is focused on the chemical reaction and separation

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Ionic liquid-based ultrasonic-assisted extraction (ILUAE) was successfully applied to the extraction of the four chromones (prim-O-glucosylcimifugin, cimifugin, 5-O-methylvisammioside, and sec-O-glucosylhamaudol) from Saposhnikovia divaricata (Radix Saposhnikoviae) for the first time. A series of l-alkyl-3-methylimidazolium ILs differing in anion and cation compositions was evaluated for extraction efficiency, and [C3MIM]Br was selected as the optimal solvent. In addition, ultrasound extraction parameters were optimized, and the chromones were directly quantified and analyzed by rapid resolution liquid chromatography-electrospray ionization/mass spectrometry (RRLC-ESI/MS). The optimal conditions were as follows: 0.4 M concentration of [C3MIM]Br, 20:1 solvent to solid ratio, and ultrasonic time, temperature, and frequency of 5 min, 40 °C, and 50 kHz, respectively. This approach obtained the highest extraction yield of 10.188 ± 0.473 mg g−1 for total chromones. Compared with regular UAE, the proposed approach exhibited a higher efficiency (61.56% increase) and shorter extraction time (nine times shorter). Also, ILUAE was an efficient, rapid, and simple sample preparation technique for extraction of chromones, and the established RRLC-DAD method could serve as a rapid and effective technique for extracting chromones from Radix Saposhnikoviae.

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alternative solvents for separations, chemical synthesis, electrochemistry and catalysis. Generally, they are nonvolatile, non-explosive, recyclable, easy to handle and thermally robust. The work on deep desulfurization by ionic liquids was well summarized in

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Introduction Ionic liquids (ILs) have a widespread use in many areas of chemistry due to features of first-rate chemical and thermal stabilities, good electronic and ionic conductivities and ability to dissolve a great variety

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and 43% ee% for α-methylstyrene. It would be of interest if we could shorten the reaction time and improve the enantioselectivity of the asymmetric reaction without the use of volatile organic solvent. Room temperature ionic liquids (RTILs) are

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Introduction Room Temperature Ionic Liquids (RTILs) are a class of organic molten electrolytes which are liquids around room temperature [ 1 ]. They have specific properties such as negligible vapour pressures, high ionic

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Room temperature ionic liquids are a new class of solvents of potential interest for liquid chromatography. Ionic liquids possess a combination of physical and solvation properties that are complementary to conventional organic solvents. Applications in liquid chromatography are currently limited by their unfavorable viscosity and low-wavelength absorption in the ultraviolet (UV) region. In addition, for planar chromatography, the absence of a vapor pressure does not allow evaporation of ionic liquid solvents after development. The room temperature ionic liquids are good solvents for nonionic compounds with a different blend of intermolecular interactions compared with conventional organic solvents as indicated by solvatochromic measurements and the system constants of the solvation parameter model. Current applications in column and planar chromatography are reviewed to demonstrate the potential of room temperature ionic liquids as mobile phases or mobile phase additives in separation science. A real breakthrough in their use, however, requires the identification of new room temperature ionic liquids with viscosity closer to those of conventional organic solvents as well as addressing other minor issues described in the text.

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