The Experts below are selected from a list of 833790 Experts worldwide ranked by ideXlab platform
Georges Guiochon - One of the best experts on this subject based on the ideXlab platform.
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monolithic columns in high performance Liquid Chromatography
Journal of Chromatography A, 2007Co-Authors: Georges GuiochonAbstract:Monolithic media have been used for various niche applications in gas or Liquid Chromatography for a long time. Only recently did they acquire a major importance in high-performance column Liquid Chromatography (HPLC). The advent of monolithic silica standard- and narrow-bore columns and of several families of polymer-based monolithic columns has considerably changed the HPLC field, particularly in the area of narrow-bore columns. The origin of the concept, the differences between their characteristics and those of traditional packed columns, their advantages and drawbacks, the methods of preparation of monoliths of different forms, and the current status of the field are reviewed. The actual and potential performance of monolithic columns are compared with those of packed columns. Monolithic columns have considerable advantages, which makes them most useful in many applications of Liquid Chromatography. They are extremely permeable and offer a high efficiency that decreases slowly with increasing flow velocity.
Xiang Fan Piao - One of the best experts on this subject based on the ideXlab platform.
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Research on Multidimensional Liquid Chromatography Sample Pretreatment System
Applied Mechanics and Materials, 2014Co-Authors: Peng Wang, Jun Cai, Xiang Fan PiaoAbstract:Using multidimensional Liquid Chromatography technology, a Liquid Chromatography sample pretreatment system which was controlled by a microcontroller was designed. Real sample pretreatment experiments have been done. The experimental results showed that the complex samples can be separated effectively with this system according to 3 polarities. The operation of this system is simple, fast and high automatic, which meet the requirements of pretreatment of Liquid Chromatography complex samples.
Toshihiko Hanai - One of the best experts on this subject based on the ideXlab platform.
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Quantitative Explanation of Retention Mechanisms in Reversed-phase Mode Liquid Chromatography, and Utilization of Typical Reversed-phase Liquid Chromatography for Drug Discovery
Current Chromatography, 2019Co-Authors: Toshihiko HanaiAbstract:The retention mechanism in reversed-phase Liquid Chromatography was quantitatively described using log P (octanol-water partition coefficient). The hydrophobic (lipophilic) interaction Liquid Chromatography was then used to measure the hydrophobicity of a variety of compounds. Furthermore, the technique has been used as an analytical method to determine molecular properties during the drug discovery process. However, log P values cannot be applied to other chromatographic techniques. Therefore, the direct calculation of molecular interactions was proposed to describe the general retention mechanisms in Chromatography. The retention mechanisms in reversed-phase Liquid Chromatography were quantitatively described in silico by using simple model compounds and phases. The competitive interactions between a bonded-phase and a solvent phase clearly demonstrated the retention mechanisms in reversed-phase Liquid Chromatography. Chromatographic behavior of acidic drugs on a pentyl-, an octyl-, and a hexenyl-phase was quantitatively described in the in silico analysis. Their retention was based on their hydrophobicity, and hydrogen bonding and electrostatic interaction were selectivity of the hexenyl-phase. This review focuses on the quantitative explanation of the retention mechanisms in reversed-phase Liquid Chromatography and the practical applications in drug discovery.
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Hydrophilic Interaction Liquid Chromatography for LC-MS
Mass Spectrometry & Purification Techniques, 2018Co-Authors: Toshihiko HanaiAbstract:The retention mechanisms in hydrophilic interaction Liquid Chromatography (HILIC) are quantitatively described in in silico analysis. Among a variety of polar bonded-phase silica gels, hexylamine-bonded silica gel is stable and can be used in both aqueous HILIC and ion-exchange Liquid Chromatography with high reproducibility. Hexynyl and phenylhexyl bonded silica gels are also used in HILIC with high reproducibility. The retention mechanisms in aqueous hydrophilic and non-aqueous hydrophilic (normal-phase) Liquid Chromatography are similar. Both hydrogenbonding and weak electrostatic interaction contributes to retention. Furthermore, strong electrostatic interaction is dominant in ion-exchange Liquid Chromatography. A suitable Liquid chromatographic system for Liquid Chromatography (LC)-mass spectrophotometer (MS) is proposed.
Shengqiang Tong - One of the best experts on this subject based on the ideXlab platform.
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Liquid-Liquid Chromatography in enantioseparations
Journal of Chromatography A, 2020Co-Authors: Shengqiang TongAbstract:Abstract Modern Liquid-Liquid Chromatography mainly refers to the following two kinds of chromatographic apparatuses: countercurrent Chromatography based on hydrodynamic equilibrium systems and centrifugal partition Chromatography based on hydrostatic equilibrium systems. In this paper, the recent advancements in enantioseparations by Liquid-Liquid Chromatography, including the separation mechanism, chiral selector, two-phase solvent system, methods to improve the peak resolution and recent applications, are reviewed. The future outlook for Liquid-Liquid Chromatography in enantioseparations is also proposed.
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Liquid-Liquid Chromatography in sample pretreatment for quantitative analysis of trace component in traditional Chinese medicines by conventional Liquid Chromatography
Journal of Chromatography A, 2020Co-Authors: Shanshan Zhao, Chaoyue Wang, Xiang Wang, Yang Jin, Wenyu Sun, Xingchu Gong, Shengqiang TongAbstract:Abstract A method for sample pretreatment using Liquid-Liquid Chromatography combined with a conventional Liquid Chromatography was developed for quantitative determination of trace chemical component in traditional Chinese medicine. The main effective component, wilforlide A, in the traditional Chinese medicinal herb Tripterygium wilfordii as well as in its Chinese patent medicine glycosides tablets was successfully determined after sample pretreatment by Liquid-Liquid Chromatography. A biphasic solvent system n-hexane-ethyl acetate-ethanol-water (6:4:6:4, v/v) was screened for crude sample treatment by Liquid-Liquid Chromatography. The collection time of eluted fractions containing target component could be well predicted using a continuous-stirred tank reactors model after determination of its retention time. Then, quantitative analysis of wilforlide A in Tripterygium wilfordii as well as in its tablets could be successfully determined by conventional reversed-phase high performance Liquid Chromatography with UV detector. Under the optimized conditions, the method showed good linearity (R2 = 0.9999) for wilforlide A in the range of 0.01 mg mL−1 −0.10 mg mL−1. The limit of detection and limit of quantity were 1.35 ng mL−1 and 4.50 ng mL−1, respectively. The average recovery rate, intra-day and inter-day precisions of wilforlide A were 96.43%, 0.67% and 1.14%, respectively. Compared with previous studies, the present method showed advantages of complete recovery of target component in the sample pretreatment and good repeatability.
Peng Wang - One of the best experts on this subject based on the ideXlab platform.
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Research on Multidimensional Liquid Chromatography Sample Pretreatment System
Applied Mechanics and Materials, 2014Co-Authors: Peng Wang, Jun Cai, Xiang Fan PiaoAbstract:Using multidimensional Liquid Chromatography technology, a Liquid Chromatography sample pretreatment system which was controlled by a microcontroller was designed. Real sample pretreatment experiments have been done. The experimental results showed that the complex samples can be separated effectively with this system according to 3 polarities. The operation of this system is simple, fast and high automatic, which meet the requirements of pretreatment of Liquid Chromatography complex samples.
