Use of Database of Plots of Pesticide Retention (R F ) Against Mobile-Phase Compositions for Fractionation of a Mixture of Pesticides by Micropreparative Thin-Layer Chromatography

Relationships between R _F values and mobile-phase composition have been determined for urea herbicides and fungicides in normal-phase systems (NP) of the type silica-nonpolar or weakly polar diluent (heptane, toluene, diisopropyl ether) – polar modifier (ethyl acetate, tetrahydrofuran, dioxane, ethyl-methyl ketone and 2-propanol). These relationships constitute a retention database which has enabled to choose optimum systems for preliminary fractionation of a multicomponent mixture of pesticides by zonal micropreparative TLC. The mixture was applied from the edge of the layer in the frontal + elution mode which increased the separation efficiency because or displacement effects. The separated simpler fractions were applied to a silica plate and rechromatographed. The plate was videoscanned, furnishing a real picture of the plate showing preliminary separation of the simpler pesticide fractions. Complete separation of the fractions was carried out by two-dimensional thin-layer chromatography on plates with chemically bonded-cyanopropyl silica stationary phase using non-aqueous eluent in the first direction and aqueous reversed-phase eluent in the second direction.     

Separation of alkylnaphthalenes by preparative liquid chromatography using column switching systems

Summary The paper describes the separation of the mixture of alkynaphthalenes from distillation cuts of a pyrolysis oil, by preparative liquid chromatography on silica. The design of the system permits the connection of the columns to form multicolumn systems.The samples were first separated on a single column. The mixtures were further separated using two-column chromatography systems.The obtained fractions were analyzed by capillary gas chromatography. In most cases a substantial increase in the concentrations of the individual components was achieved. In several cases, pure compounds have been obtained. Separation efficiency increases in the following order: single column, two directly coupled collumns, two-step switching chromatography, heartcutting.     

Off-line combination of reversed-phase liquid chromatography and laser desorption/ionization time-of-flight mass spectrometry with seamless post-source decay fragment ion analysis for characterization of square-planar nickel(II) complexes

Characterization of square-planar nickel(II) complexes of the Schiff base of (S)-N-benzylproline (2-benzoylphenyl)amide and various amino acids that are used as efficient alpha-amino acids synthons was carried out using laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF MS) in off-line combination with liquid chromatography. A mixture of four square-planar nickel(II) complexes was separated using reversed-phase liquid chromatography (RPLC) and the separated fractions from the chromatographic run were spotted on the metal target directly from the column outlet using a lab-made sample deposition device. The separated fractions were then analyzed by LDI-TOF MS. Seamless postsource decay (sPSD) fragment ion analysis was used for their structural characterization, which made possible the confirmation of expected chemical structures of the analyzed compounds. The off-line combination of the separation by RPLC and analysis by LDI-TOF MS allowed successful separation, sensitive detection and structure elucidation of the square-planar nickel(II) complexes.     

木质素分散剂相对分子质量分布的测定

 利用凝胶渗透色谱法测定了木质素分散剂的相对分子质量分布。结果表明,Reax-85A相对分子质量分布为500～35000,M-9为1000～50000。Reax-85和M-9各薄层分离组分的相对分子质量分布的测定结果说明,组分Rf值越大,流出体积越大,相对分子质量越小。NaOH溶液的浓度对洗脱图形有很大影响,当其浓度为0.5mol/L时图形趋于稳定。     

径向展开薄层色谱法分离生物碱及其分离效能

径向展开薄层色谱法是一种将样品由中心沿径向向外展开的简便、快速、高效的色谱方法。该文组装了简单的径向展开薄层色谱装置,并建立了朱砂安神丸的径向展开薄层色谱检测法,对其中的生物碱成分进行分离,研究了径向展开薄层色谱的分离特性。从薄层色谱基础理论出发,对径向展开薄层色谱和一般薄层色谱的分离效能进行了比对研究,设计试验进行计算和求解。证明了径向展开薄层色谱法更快、更高效、更经济,适用于生物碱等高极性样品分离。探索了径向展开薄层色谱法高分离效率的理论根源,这一研究思路也为理论创新提供了新的方法和思路。     

高效液相色谱-基质辅助激光解吸电离串联飞行时间质谱分离鉴定牛乳铁蛋白素

建立了高效液相色谱-基质辅助激光解吸电离串联飞行时间质谱(MALDI-TOF/TOF MS)分离鉴定牛乳铁蛋白素(bovine lactoferricin, LfcinB)的方法。采用胃蛋白酶酶解牛乳铁蛋白,酶解液离心后取上清液,经过离子交换色谱、反相液相色谱、透析等技术分离,对分离得到的目标产物进行抗菌活性分析、蛋白含量测定和MALDI-TOF/TOF MS鉴定。分离得到高活性的LfcinB,其相对分子质量为3124.89,蛋白含量为18.20 μg/mL。本方法具有精度高、分析速度快和分辨能力强等优点,是其他传统的分析鉴定LfcinB方法所无法比拟的,为进一步研究LfcinB奠定了基础。     

Bildung siliciumorganischer Verbindungen. XXXVII1,3,5,7-Tetrasila-adamantane aus der Pyrolyse des (CH3)3SiCl und Auftrennung des Pyrolysegemisches

Further separation of the pyrolysis products of (CH₃)₃SiCl can be achieved by reaction with LiAlH₄/LiH (transfer of SiCl to SiH groups). By means of adsorptions chromatography a separation is obtained into 4 groups of components. By application of gel chromatography (sephadex LH 20) separation is improved, thus fractions of carbosilanes are found with average molecular weights between 5000 and 200. A given mixture of the compounds [5], [9], [10] has been separated by means of gel chromatography so that pure compounds were obtained. The mixture of the 1,3,5,7-Tetrasila-adamantanes, which are formed in the pyrolysis of (CH₃)₃SiCl, is separated by gel chromatography (efficiency control of separation is performed by NMR and mass spectrography of the different fractions), a concentration of some compounds is obtained, some of them are isolated purely by further operations. The ratio of the compounds [1], [2], [3], [4], found in the pyrolysis products, is 170:26:3:1. Derivatives are formed with SiH, SiCl, and SiCH₃ groups by complete or respectively partial hydrogenation. Comparing the values of the chemical shift of the CH₃-protones [measured in τ) a linear decrease is found in the compounds [9], [4], [3], [2].     

Isolation and Characterization of Sulfur-Containing Polycyclic Aromatic Compounds (Thia-Arenes) from Complex Environmental Mixtures

Abstract

A multi-dimensional chromatographic method was developed and applied to the separation of thia-arenes and polycyclic aromatic hydrocarbons (PAH) derived from coal tar. A thia-arene-rich fraction, prepared using a combination of alumina chromatography and palladium chloride/silica gel chromatography, was further separated using normal phase HPLC to isolate fractions containing thia-arenes with molecular masses ranging from 184 amu to 284 amu. These fractions were analysed using gas chromatography-mass spectrometry; approximately one-half of the thia-arenes in a coal tar extract were retained and separated by the palladium chloride-silica gel step. This methodology has been successfully applied to coal tar, air particulate material, sediments and biological samples.     

高温二维液相色谱系统的构建及其评价

在二维液相色谱中, 第二维的分离速度是制约其发展的重要因素. 升高色谱柱温度可以有效降低流动相粘度, 加快溶质在两相间的传质速率, 有效加快分析速度. 以离子交换色谱法(WAX)为第一维分离模式和反相色谱法(RP)为第二维分离模式, 十通阀和两个捕集柱为接口, 通过将第二维色谱柱温度升高到80 ℃和提高流量到3 mL/min, 构建了高温WAX/RP二维液相色谱系统. 以4种标准蛋白的酶解物为样品评价系统的分离性能, 第一维共有33个馏分被捕集并导入到第二维分析, 高温二维液相色谱系统识别出187个色谱峰.     

CSE-MECC two-dimensional capillary electrophoresis analysis of proteins in the mouse tumor cell (AtT-20) homogenate

Two-dimensional capillary electrophoresis was used for the separation of proteins and biogenic amines from the mouse AtT-20 cell line. The first-dimension capillary contained a TRIS–CHES–SDS–dextran buffer to perform capillary sieving electrophoresis, which is based on molecular weight of proteins. The second-dimension capillary contained a TRIS–CHES–SDS buffer for micellar electrokinetic capillary chromatography. After a 61-s preliminary separation, fractions from the first-dimension capillary were successively transferred to the second-dimension capillary, where they further separated by MECC. The two-dimensional separation required 60 min.     

原油非烃化合物结构与含量的馏分分离及联用色谱信息获取通用方法

用正己烷将沥青质从油样中分离,再根据类组分之间极性差别,用中性氧化铝-硅胶双层析柱将原油样其余部分分成脂肪烃、芳香烃和7个非烃馏分。各馏分回收完全。用色-质联用技术,将非烃馏分再分离并获取实验数据,为原油非烃结构和含量测定奠定有关的信息基础。不同油井样品研究和重复实验表明,方法对各种原油非烃化合物分离和信息测定有很好的重现性。     

柱状假丝酵母脂肪酶同工酶的一种高效液相色谱分离新方法

建立一种“疏水界面亲和色谱”分离柱状假丝酵母脂肪酶同工酶的高效液相色谱新方法。将商品化的CRL经离子交换色谱分离为两个同工酶组分 (CRLA和CRLB) ,在极低离子强度下 ,根据同工酶活性中心周围处于“开放”构象的疏水腔具亲疏水界面的特性 ,用疏水界面亲和色谱在NucleosilC4 (10 μ ,3 0 0 ,2 5 0× 4.60mm)柱上将CRLA和CRLB都分离为 4种同工酶组分。疏水界面亲和色谱非常适用于分离这种结构差异轻微的同工酶组分     

Identification Of Oxygen Derivatives Of Polycyclic Aromatic Hydrocarbons In Airborne Participate Matter Of Upper Silesia (Poland)

Abstract

Organic material extracted from airborne participate matter collected in various places of Upper Silesia has been separated by column liquid adsorption chromatography. Six fractions of different polarity have been eluted. These fractions have undergone careful spectral analysis, thin layer chromatography and gas chromatography-mass spectrometry. Several PAH oxygen derivatives which have not been found in air from our Region so far were identified. Their biological activity is higher than activity of basic PAH structures. These compounds can be responsible to a high degree for interference in living organism functions in this highly polluted region.     

核磁共振和液相色谱-质谱平行动态谱学方法对连翘活性提取物的同步结构分析

以连翘植物的活性提取物为研究对象,基于不完全分离分析策略,以制备型HPLC技术为分离手段,获取含量呈连续动态变化的系列混合物,运用NMR/LC-MS 平行动态谱学方法对提取物中苯乙醇苷类成分进行了同步结构分析研究.采用本方法可获取系列提取物样品中同一成分内在相关且互补的谱学信息,包括保留时间、质荷比(m/z)和化学位移...     

A miniaturized multichamber solution isoelectric focusing device for separation of protein digests

A miniaturized multichamber device was constructed for solution isoelectric focusing (IEF) separation of complex peptide mixtures. The system, based on immobilized pH gels, consisted of 96 minichambers ( approximately 75 nuL each) arranged in eight rows. Neighboring chambers in a given row were separated by short glass tubes (4 mm inner diameter, 3 mm long), within which Immobiline gels of specific pH values were polymerized. During focusing, the device was sandwiched between two supporting blocks incorporating the reservoirs for anolyte and catholyte. In principle, multiple samples could be simultaneously fractionated, each separated into 12 fractions of various pI ranges. A variety of standard peptide mixtures and tryptic digests of proteins were separated by IEF using this device, and the fractions were characterized by mass spectrometry. For a codigested nine-protein mixture, both the total number of peptides identified and the average sequence coverage were similar to the results of ion-exchange chromatography (IEC), according to matrix assisted laser/desorption/ionization--time of flight (MALDI-TOF) data. The IEF separation provided concentrated and desalted fractions, suitable for an additional separation liquid chromatography, capillary electrophoresis (LC, CE) or mass spectrometry (MS) detection without additional sample cleanup. High loading capacity was achieved for the miniaturized multichamber IEF device. Importantly, a linear correlation was found between the experimentally determined and calculated pI values of peptides.     

Fractionation of the human plasma proteome for monoclonal antibody proteomics-based biomarker discovery

mAb proteomics, a reversed biomarker discovery approach, is a novel methodology to recognize the proteins of biomarker potential, but requires subsequent antigen identification steps. While in case of high-abundant proteins, it generally does not represent a problem, for medium or lower abundant proteins, the identification step requires a large amount of sample to assure the proper amount of antigen for the ID process. In this article, we report on the use of combined chromatographic and precipitation techniques to generate a large set of fractions representing the human plasma proteome, referred to as the Analyte Library, with the goal to use the relevant library fractions for antigen identification in conjunction with mAb proteomics. Starting from 500?mL normal pooled human plasma, this process resulted in 783 fractions with the average protein concentration of 1?mg/mL. First, the serum albumin and immunoglobulins were depleted followed by prefractionation by ammonium sulfate precipitation steps. Each precipitate was then separated by size exclusion chromatography, followed by cation and anion exchange chromatography. The 20 most concentrated ion exchange chromatography fractions were further separated by hydrophobic interaction chromatography. All chromatography and precipitation steps were carefully designed aiming to maintain the native forms of the intact proteins throughout the fractionation process. The separation route of vitamin D-binding protein (an antibody proteomics lead) was followed in all major fractionation levels by dot blot assay in order to identify the library fraction it accumulated in and the identity of the antigen was verified by Western blot.     

SEPARATION AND PHOTOTOXICITY IN VITRO OF SOME OF THE COMPONENTS OF HAEMATOPORPHYRIN DERIVATIVE

Abstract— The separation and fractionation of some of the components of haematoporphyrin derivative by chemical extraction, gel chromatography and membrane filtration are described. The composition of the various fractions and the purity of the individual porphyrins can be assessed by high performance liquid chromatography. Porphyrins containing vinyl side chains show an unusual ability to form relatively stable aggregates of apparently high molecular weight. The effect is most pronounced with protoporphyrin and is not observed with haematoporphyrin which has no vinyl side chains. These aggregates can be separated by gel chromatography or membrane filtration from non (or less) aggregated material. The aggregates show greater in vitro cytotoxicity than the other fractions.     

Research on the separation properties of empty-column gas chromatography (EC-GC) and conditions for simulated distillation (SIMDIS)

Previous studies have revealed it is possible to separate a high-boiling mixture by gas chromatography in empty fused-silica capillary tubing rather than in columns coated with stationary phase. Chromatographic separation occurs solely on the basis of the different boiling points of the substances separated. The high similarity of such separations to those in classic distillation seems advantageous when gas chromatography is used for simulated distillation. This paper presents results from further research on the separation properties of empty fused silica tubing. The efficiency of this chromatographic system has been examined. The usefulness of such conditions has been studied for simulated distillation, i.e. to determine the boiling-point distribution of complex mixtures, mainly petroleum fractions and products, on the basis of their retention relative to reference substances. The results obtained by use of empty-column gas chromatography (EC-GC) and by use of classical simulated distillation columns have been compared for solutes of different polarity. Studies revealed boiling points determined by EC-GC were more accurate than those obtained by the standard method of simulated distillation.     

Implementations of two-dimensional liquid chromatography

Today scientists must deal with complex samples that either cannot be adequately separated using one-dimensional chromatography or that require an inordinate amount of time for separation. For these cases we need two-dimensional chromatography because it takes far less time to generate a peak capacity n(c) twice in a row than to generate a peak capacity n(c)(2) once. Liquid chromatography has been carried out successfully on thin layers of adsorbents and along tubes filled with various adsorbents. The first type of separation sorts out the sample components in a physical separation space that is the layer of packing material. The analysis time is the same for all the components of the sample while their migration distance increases with decreasing retention. The resolution between two components having a certain separation factor (alpha) increases with increasing migration distance, i.e., from the strongly to the weakly retained compounds. In the second type of separation, the sample components are eluted from the column and separated in the time space, their migration distances are all the same while their retention times increase from the unretained to the strongly retained compounds. Separation efficiency varies little with retention, as long as the components are eluted from the column. We call these two types of separation the chromatographic separations in space (LC(x)) and the chromatographic separations in time (LC(t)), respectively. In principle, there are four ways to combine these two modes and do two-dimensional chromatographic separations, LC(t)xLC(t), LC(x)xLC(t), LC(t)xLC(x), and LC(x)xLC(x). We review, discuss and compare the potential performance of these combinations, their advantages, drawbacks, problems, perspectives and results. Currently, column-based combinations (LC(t)xLC(t)) are the most actively pursued. We suggest that the combination LC(x)xLC(t) shows exceptional promise because it permits the simultaneous second-dimension separations of all the fractions separated in the first-dimension, thus providing remarkable time saving.     

Preparative separation of cichoric acid from Echinacea purpurea by pH-zone-refining counter-current chromatography

pH-zone-refining counter-current chromatography was successfully applied to the separation of cichoric acid from Echinacea Purpurea (L.) Moench. A 3.0 g quantity of sample was separated using the following two-phase solvent system: MtBE-CH3CN-water (4:1:5, v/v), 10 mM trifluoroacetic acid in organic stationary phase and 10 mM ammonia in aqueous mobile phase. The obtained fractions were analyzed by high-performance liquid chromatography and negative ion electrospray ionization mass spectrometry. Double separations were performed with the same solvent system yielding 563 mg cichoric acid at 95.6% purity.