Centrifugal Layer Chromatography — Rotation Planar Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - Among forced-flow layer chromatographic techniques, the centrifugally-driven variety was first developed, and named centrifugal...     

Studies on Chromatography Fingerprint of Hongqi by High-performance Liquid Chromatography

Chromatography fingerprint (CFP) of 10 samples of hongqi were studied. 23 commonpeaks were analyzed, their average similarity was 97.29%. CFP were positioned with main indexcomposition such as formononetin, calycosin and then the contents of index composition weredetermined. The character and exclusive of CFP of 10 samples of hongqi were clear. CFP andcontent determination of index composition of hongqi could be used to evaluate the quality of hongqicomprehensively.     

Chiral Separations by Ligand-Exchange Micellar Electrokinetic Chromatography and Microemulsion Electrokinetic Chromatography

heseparationofenantiomersisofgreatim portanceinbiology ,pharmaceutics ,agricultureandenvironment .Thedifferentseparationmodes (i e capillaryzoneelectrophoresis (CZE) ,micellarelec trokineticchromatography (MEKC) ,capillaryelec trochromatography (CEC) ,etc…     

Liquid–Gas Adsorption Chromatography

The history of the discovery, physical and chemical properties, and analytical potentialities of chromatographic methods using the stationary gas phase, such as liquid–gas and liquid–gas adsorption chromatography, are considered. Taking into account the retention of the stationary gas phase in the pores of a hydrophobic support, one can optimize the conditions for the separation and extraction of volatile substances from aqueous solutions on hydrophobic adsorbents in solid-phase extraction and reversed-phase liquid chromatography. Scientific progress is the progress of a method. M.S. Tswett     

Retention Time Locking in the Determination of Narcotic Drugs by Chromatography and Chromatography–Mass Spectrometry

The use of retention time locking (RTL) in the development of unified procedures for the detection and quantitative determination of drugs in biological fluids was considered. With consideration for the use of RTL, a chromatographic procedure with flame-ionization and mass-selective detection was developed for the detection and quantitative determination of opiates and their synthetic analogs; phenylalkylamine derivatives; cocaine; ketamine; and other narcotic drugs, their derivatives, and metabolites in urine. The analytical ranges for chromatography–mass spectrometry were 0.05–1000 and 0.005–1000 g/mL under the conditions of total ion current (TIC) scanning and selected ion monitoring (SIM), respectively. With flame-ionization detection (GC–FID), the analytical range was 0.5–1000 g/mL.     

“Fundamentals of Thin Layer Chromatography”评介

薄层色谱法是一种应用领域很广的“平面色谱”技术,与“柱色谱”法有别但又互补。早在60年代初它便被介绍到我国。我们起步不晚,但至今不少工作仍停留在国外70年代中期水平上。究其原因固然与我国薄层色谱材料及仪器设备较落后有关,更主要的可能还是对其基本理论的忽视和色谱参数在实践中对结果重现的重要性认识不足。须知无论怎样精密的仪器也不可能“改造”一个分离度与重现性都差的薄层     

Polymer-Coated Fibrous Packing Materials inMetal Capillary Gas Chromatography

Gaschromatography (GC)isoneofthemostversatileseparationmethodsforvolatilecom pounds ,andavarietyofpolymericmaterialsasthestationaryphaseshavebeendevelopedforvariousapplications.Incontrasttothesuccessfulapplica tionsandcommercializationofthepolymer coatedc…     

Advances of Chromatography in Analysis of Complex Samples

The separation and identification of complex samples is an urgent task that analytical chemistry has to face. Chromatography, as an important analysis technique, has been widely applied to many fields, such as life science, environment, medicine, food and petrochemical engineering.Recently, with the progress of science and tech-     

Separation of Felted Explosives by Pressurized Microemulsion Electrokinetic Chromatography

A new MEEKC method assisted with pressure-driven mobile phase was presented for the separation of felted explosives. Microemulsion solution was composed of 80 mmol/L heptane-120 mmol/L SDS (sodium dodecyl sulphate)-900 mmol/L butanol-10 mmol/L borate at pH 9.4 and a pressure-driven flow of 0.020 mL/min under 1.3 MPa was employed to manipulate the separation. Explosives HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane) and TATB(triamino-trinitrobenzene), which were felted on fluorine rubber F2311 (polytrifluorochlorethylene and polyvinylidene fluoride 1/1 co-polymerization) and F2314 (polytrifluorochlorethylene and polyvinylidene fluoride 4/1 co-polymerization) were well separated with very good peak shapes.     

Principle and Potential of Gradient Elution in Planar Chromatography

It was the intention of this paper to show some recent developments in thin layer chroma-togrphy aiming at increasing the separation efficiency by instrumental means and techniquesusing existing separation layers. Gradient elution in the normal phase is a most efficient wayto achieve this goal. Multi-dimensional separations by coupling gradient elution column liquid chromatography inthe reversed phase with AMD gradient elution in normal phase is suitable to achieve newdimensions of separation numbers. Assuming that the N numbers reported for HPLC translateinto separation numbers near 100, by coupling the two kinds of chromatography, separationnumbers around 500 become practically usable.     

Separation of Aniline Derivatives by Micellar Electrokinetic Capillary Chromatography

A micellar electrokinetic capillary chromatography (MECC) was developed for the determination of aniline and 6 substituted anilines. The seven components were separated within 25min in the buffer solution of 40mmol/L sodium borate and 100mmol/L SDS. It was found that the separation was dependent on operating voltage, pH value, borate and SDS concentrations.The analytical performance was examined in terms of linear response and reproducibility.Wastewater was determined by the established method.     

High-Performance Liquid Chromatography of α-Substituted Acetic Acid Derivatives

Abstract

Two high-performance liquid chromatographic systems for the separation of α-substituted acetic acid derivatives are presented. The first method uses a resin-based column for organic acid separations (Polypore H) with a dilute acid as mobile phase. The second system decribes the possibilities of ion-pair high-performance liquid chromatography on a reverse phase C18 column. Special attention is given to the simultaneous optimization of the counterion and buffer concentration. The applicability is demonstrated in the quality control of [1-¹¹C]-malonic acid.     

Separation of Hydrophobic Neutral Compounds by Microemulsion Electrokinetic Chromatography

Electrokineticchromatography(EKC)istheonlymodeofcapillaryelectrophoresisfOrtheseparationofelectricalneutralcompounds.Theseparationprincipleisbasedonthedifferentpartitionofsolutesbetweenthepseudostationaryphaseandthesurroundingaqueousphase.MicellarEKC(MEKC)provideshighspeedandhighefficiencyseparationforneutralcompoundswithsignificantsolubilityinaqueoussystem'.Theseparationofhydrophobiccompounds,however,givessomeproblems,becauseoftheirpoorsolubilityinaqueousphase.Inourpreviouswork"',somepol…     

Determination of Phytomarkers in Pharmaceutical Preparations of Hemidesmus indicus Roots by Micellar Electrokinetic Chromatography and High-Performance Liquid Chromatography–Mass Spectrometry

Micellar electrokinetic chromatography was applied to the determination of the major phytomarkers, namely 2-hydroxy-4-methoxybenzaldehyde, 2-hydroxy-4-methoxybenzoic acid, and 3-hydroxy-4-methoxybenzaldehyde, of Hemidesmus indicus root, an Indian medicinal plant. H. indicus bioactive preparations were analyzed by reverse flow micellar electrokinetic chromatography (MEKC) using sodium taurodeoxycholate as the surfactant. A pH 2.5 phosphate buffer (50 mM) was supplemented with 65 mM of sodium taurodeoxycholate to produce the MEKC pseudostationary phase; because of the suppression of the electroosmotic flow, the migration of the partitioned analytes was toward the capillary anodic end. The use of a short fused-silica capillary (8.5 cm effective length; 50 μm i.d.) allowed the separation of phytomarkers, including vanillin and salicylaldehyde (reported as additional metabolites of H. indicus roots), in less than 8 min. The method showed good validation parameters and was applied to the analysis of methanol extracts and a root decoction of H. indicus, a promising botanical drug. The obtained results were compared to those from an independent high-performance liquid chromatography–mass spectrometry method. The 2-Hydroxy-4-methoxybenzaldehyde, 2-hydroxy-4-methoxybenzoic acid, and 3-hydroxy 4-methoxybenzaldehyde were found in all samples confirming their roles as phytomarkers. The absence of vanillin and salicylaldehyde suggested that these latter compounds should not be regarded as characteristic components of the bioactive preparations from the plant roots.     

Optimized Separation of Nine Xanthones by Microemulsion Electrokinetic Chromatography

A microemulsion electrokinetic chromatography method has been firstly used for the separation of the therapeutically important xanthones from Securidaca inappendiculata. The separation of the nine xanthones was systematically optimized with respect to pH, composition of microemulsion,addition of cyclodextrins, applied voltage and column temperature. Baseline separation was successfully achieved for the nine xanthones, which was also compared with that by micellar electrokinetic chromtography.     

Determination of Four Volatile Compounds with Anti-Inflammatory Biological Activity in Houttuynia chordata Thunb. by Gas Chromatography and Gas Chromatography–Mass Spectrometry

An analytical procedure was developed for the determination of four volatile components with anti-inflammatory biological activity in Houttuynia cordata Thunb. by gas chromatography and gas chromatography–mass spectrometry. Four compounds (α-pinene, β-myrcene, 1-decanol and 2-undecanone) were selected as analytes because they are common major constituents in volatile compositions of Houttuynia cordata Thunb Anti-inflammatory efficacy in vivo suggested that the four compounds provided inhibitory effects on xylene-induced ear edema formation in a dose-dependent manner. The four compounds were determined by gas chromatography in mouse serum after oral administration of volatile oil and water distillate liquid of Houttuynia cordata Thunb Related chromatographic conditions were investigated and selected. A good separation of the four compounds and internal standard was achieved. The method reflected the quality of Houttuynia cordata Thunb. and its preparations.     

Denatured Thermodynamics of Proteins in Weak Cation－exchange Chromatography

The thermostability of some proteins in weak cation-exchange chromatography was investigated at 20—80 ℃. The results show that there is a fixed thermal denaturation transition temperature for each protein. The appearance of the thermal transition temperature indicates that the conformations of the proteins are de-stroyed seriously. The thermal behavior of the proteins in weak cation-exchange and hydrophobic interaction chromatographies were compared in a wide temperature range. It was found that the proteins have a higher thermostability in a weak cation-exchange chromatography system. The thermodynamic parameters (△H^0,△S^0) of those proteins were determined by means of Van′t t Hoff re|ationship(lnk′-1/T). According to stan-dard entropy change(△S^0) , the conformational change of the proteins was judged in the chromatographic pro-cess. The linear relationships between △H^0 and △S^0 can be used to evaluate “compensation temperature“ (β) at the protein denaturation and identify the identity of the protein retention mechanism in weak cation-ex-change chromatography.     

Purification of L-Lysine in Simulated Moving Bed and Fixed-Bed Chromatography

L Lysineisanessentialaminoacidusedasafeedadditiveinanybalancedpoultrydiets ,anditisproducedbyamicrobial processthatutilizesaCorynebacterium glutamicumstrain .CommonlyL lysineisrecoveredfromculturebrothusingcationicexchange[1- 3] .Thebatchandfixed bedad so…     

Application of Gas Chromatography and Gas Chromatography–Mass Spectrometry to the Detection of γ-Hydroxybutyric Acid and Its Precursors in Various Materials

Modified procedures were developed for the detection of -hydroxybutyric acid and 1,4-butanediol (its metabolic precursor) in foods, food additives, and urine using gas chromatography and gas chromatography–mass spectrometry. The analytical range was 0.1–20 wt %.