二维液相色谱(SCX/RP)系统的构建及对珠蛋白水解产物的研究

以十通阀为切换接口, 构建了SCX/RP常规柱二维液相色谱系统, 并以珠蛋白水解产物的分析对其加以评价. 样品首先由第一维阳离子交换色谱(Hypersil SCX, 100 mm×4.6 mm I.D.)在pH 4.0的磷酸盐缓冲体系中分离, 洗脱产物进入切换接口, 样品组分被富集在捕集柱(Hypersil BDS C18, 15 mm×4.6 mm I.D.)中, 进一步脱盐后被导入第二维反相色谱(Hypersil BDS C18, 250 mm×4.6 mm I.D.)分离分析. 阳离子交换色谱采用逐步增加盐浓度的12步台阶等度间断方式洗脱, 每次将洗脱产物捕集在捕集柱中进而由反相色谱分析, 实现对第一维洗脱产物的切割转移及第二维分析. 与一维色谱相比, 二维液相色谱系统的分辨率、峰容量也得到提高, 系统峰容量达到2280.     

真空溶剂蒸发全二维液相色谱接口及其应用

以正相色谱(NPLC)为第一维,反相色谱(RPLC)为第二维,建立了真空溶剂蒸发接口的全二维液相色谱系统(VEI-C2DLC)。样品首先在第一维(CN色谱柱)进行正相分离,第一维洗脱产物被交替存储到十通阀上的两个定量环中,与此同时对切割到定量环内的第一维组分进行在线真空蒸发,被分析样品组分保留在定量环内壁内,而溶剂被蒸发除去。十通阀切换后保留在该定量环内的样品组分被洗脱到第二维进行反相分离,如此反复循环使第一维组分完全转移到第二维。采用标准样品和天然植物蛇床子提取液对该全二维液相系统进行了评价。     

在线二维液相色谱技术在中药研究中的应用进展

中药的组成复杂,其化学成分的表征和识别一直是中药研究的基础和关键。在线二维液相色谱是基于两种分离模式构建的色谱分析技术,主要包括中心切割二维液相色谱和全二维液相色谱两种模式,因二者具有更高的峰容量而在中药研究中备受青睐。该文对在线二维液相色谱技术的概念和特点进行了讨论,并对二维液相色谱在中药研究中的应用进行了综述,以期为该技术在中药质量控制、物质基础表征、活性成分筛选等研究方面提供一定参考。     

全二维液相色谱的初步构建及其在山羊血清分离中的应用

以GFC/RP模式构建全二维液相色谱系统,第一维凝胶过滤色谱柱使用ShodexProteinKW 802. 5(300mm×8mmi.d. ),以0. 2mol/LNaH2PO4 (pH7. 0)的流动相在0. 15mL/min的流速下等度洗脱,第二维反相色谱柱使用HypersilBDSC18 (35mm×4. 6mmi.d. ),在3mL/min的流速下梯度洗脱。采用平行柱交替分析的形式作切换接口, 2. 5min切换一次,两个反相柱交替富集、分析第一维洗脱产物。以5个标准蛋白混合物的分离评价该系统,在单独一维模式中不能分离的样品在全二维液相色谱中得到了较好的分离,二维系统的总峰容量为225。与一维色谱相比,系统的总峰容量、分辨率得到较大提高。并用于山羊血清的纯化分析,对一维分离中的重合谱峰进行验证,对制备纯化有一定的实际意义。     

开管毛细管色谱柱的制备及其在蛋白质组学研究中的应用进展

近年来随着生命科学等领域的深入发展,人们对微量样本分离分析的需求越来越高,液相色谱系统的微量化受到了更多的关注。由于开管毛细管色谱柱具有较低的反向压力,可通过采用更长的色谱柱提高柱效,从而实现对复杂生物样本的高效分离,因而成为液相色谱柱新的发展方向。本文对开管毛细管色谱柱的制备方法及应用进展进行了综述。     

全二维液相色谱（NPLC×RPLC）接口及其应用

用内径为0．53mm的填充毛细管正相液相色谱为第一维，用4．6mm（i．d．）×50mmRP-18e整体柱反相色谱为第二维，建立了定量环一阀切换接口的全二维液相色谱系统（NPLC×RPLC）．第一维色谱分离洗脱出的组分交替存储在十通阀上的两个定量环中，同时定量环中前一个组分被转移到第二维进行反相分离．因为第一维的流动相流量仅是第二维的1／500，自然解决了流动相兼容问题．采用芳香族化合物的混合物和中药丹参正己烷提取液对该全二维液相系统的分离能力进行了评价．     

全二维液相色谱(NPLC×RPLC)接口及其应用

用内径为0.53 mm的填充毛细管正相液相色谱为第一维, 用4.6 mm(i.d.)×50 mm RP-18e整体柱反相色谱为第二维, 建立了定量环-阀切换接口的全二维液相色谱系统(NPLC×RPLC). 第一维色谱分离洗脱出的组分交替存储在十通阀上的两个定量环中, 同时定量环中前一个组分被转移到第二维进行反相分离. 因为第一维的流动相流量仅是第二维的1/500, 自然解决了流动相兼容问题. 采用芳香族化合物的混合物和中药丹参正己烷提取液对该全二维液相系统的分离能力进行了评价.     

二维液相色谱切换技术及其应用

多维液相色谱已成为复杂样品研究的重要工具。本文在介绍多维液相色谱原理与方法的基础上,重点讨论了二维液相色谱接口切换技术的近期发展,并对其应用现状进行了总结分析。     

二维液相色谱接口技术

二维液相色谱具有峰容量大、分辨率高、分析速度快等优点,已经成为复杂样品分离分析的重要工具。两种分离模式的转换通常需要经过一个特殊接口来完成,接口是二维液相色谱系统的核心,也是限制二维液相色谱应用的瓶颈;两种流动相不互溶时,接口尤为重要。本文针对二维液相色谱接口技术近期的发展和应用进行总结。引用文献51篇。     

二维液相色谱阀切换接口技术的发展及应用

在复杂样本分析中,一种分离模式往往不能提供足够的分离度,组合不同的分离模式构建二维液相色谱系统是解决这一问题的有效途径。阀切换接口是二维液相色谱柱切换技术的核心,接口技术影响系统的分离度和灵敏度。传统的接口技术在生物、药学、食品、环境等领域得到了广泛应用,近20年发展了众多新型的接口技术来解决二维液相色谱中正交组合溶剂不兼容问题。本文综述了柱切换接口技术的原理和应用,并总结了近5年利用柱切换二维液相分析技术的进展,期望为二维液相色谱技术的发展和应用提供借鉴。     

On-line parallel reversed phase two-dimensional liquid chromatography for high-throughput analysis of complex proteomic samples

A comprehensive two-dimensional liquid chromatographic system (2D SCX/RP) is con- structed with a 10-port-2-way valve using strong cation exchange chromatography (Hypersil SCX, 100 mm×4.6 mm I.D.) followed by reversed phase chromatography (Hypersil BDS C18, 15 mm×4.6 mm I.D.) to separate the complex peptides from globin peptic hydrolysate. After the sample was loaded on the SCX column, the phosphate buffer (pH 4.0) was used to elute the peptides. Then, elutes flowed through the interface and the peptides focused on the head of the trapping columns (Hypersil BDS C18, 15 mm×4.6 mm I.D.) but salt passed into the waste. After the valve was switched, the samples were flushed with a backward flow into the RP analytical column. The peptides on the SCX were eluted with 12 discontinuous steps linearly increasing salt concentrations. The peptides enriched on the trapping column were desalted and separated by the RP columns. The resolution and the resolved peaks of the 2D SCX/RP system were greatly increased and the total peak capacity reached as high as 2280.     

Data analysis programs for comprehensive two-dimensional chromatography

User-friendly and easy-to-use laboratory-written programs for visualisation and interpretation of comprehensive two-dimensional chromatographic data were developed. The programs that are not tied to any particular commercial instrument, and data obtained either by comprehensive two-dimensional liquid (LC × LC) or gas (GC × GC) chromatography can be analysed. Operations of the programs allow visualisation of 2D and 3D plots, comparison of two 2D plots at a time, as well as determination of retention times and peak heights and volumes.     

多维液相色谱分离技术及其在蛋白质组研究中的应用

对近年来多维液相色谱技术及其在蛋白质组学研究中的应用进行了系统综述。详细描述了由不同液相色谱模式构建的多维液相色谱系统,并介绍了其在蛋白质组表达谱、翻译后修饰、定量等方面的应用。此外,还对多维液相色谱的发展趋势和前景进行了展望。     

Characterization of the polyphenolic fraction of pomegranate samples by comprehensive two-dimensional liquid chromatography coupled to mass spectrometry detection

Abstract

Punica granatum L., commonly known as pomegranate, is an ancient fruit widely consumed all over the world as fresh fruit or juice. In addition, it is extensively used in therapeutic formulas, cosmetics and food seasonings. The fruit is native to Afghanistan, Iran, China and the Indian sub-continent. The pomegranate market has steadily grown, presumably due to the increasing demand of health-conscious consumers for products with potential beneficial effects on human health, due to the synergistic presence of a unique and complex phytochemical composition that enclose anthocyanins, phenolic acids and hydrolysable tannins. Conventionally, for their analysis liquid chromatography is employed even though it can present some drawbacks in terms of resolving power. In this contribution, as a valuable alternative, comprehensive two-dimensional liquid chromatography with “shifted gradients” in the second dimension, was applied for the characterization of three pomegranate samples, leading to the identification of 37 different polyphenolic compounds.     

Characterization of hydroxypropylmethylcellulose (HPMC) using comprehensive two-dimensional liquid chromatography

Various hydroxyl-propylmethylcellulose (HPMC) polymers were characterized according to size and compositional distributions (percentage of methoxyl and hydroxyl-propoxyl substitution) by means of comprehensive two-dimensional liquid chromatography (LC×LC) using reversed-phase (RP) liquid chromatography in the first dimension and aqueous size-exclusion chromatography (aq-SEC) in the second dimension. RP separation was carried out in gradient-elution mode applying 0.05% TFA in water and 1-propanol, while 0.05% TFA in water was used as mobile phase in aqueous SEC. A two-position ten-port switching valve equipped with two storage loops was used to realize LC×LC. Detection of HPMC was accomplished by charged-aerosol detection (CAD). Data processing to visualize chromatograms was carried out using Matlab software. The significant influence of the LC×LC temperature on (the retention of) HPMC was studied using a column oven which allowed accurate temperature control. Due to the phenomenon of thermal gelation, which is a result of methyl and hydroxypropyl substitution of anhydroglucose units from the cellulose backbone, we were able to obtain additional, specific information on compositional characteristics of various HPMC samples. As the retention behaviour of gelated and non-gelated polymer proved to be different, the fraction of the polymer that is gelated in the chromatographic column could be monitored at different temperatures. Moreover, the temperature at which half of the polymer is gelated could be correlated with the cloud-point temperature. As a result, differences in inherent cloud points of modified cellulose can be used as a further distinguishing property in "temperature-responsive" LC×LC.     

Comprehensive two-dimensional liquid chromatography coupled with mass spectrometry

In this review, instrumental aspects of comprehensive two-dimensional liquid chromatography coupled with mass spectrometry are presented. The milestones of LC×LC are briefly summarized. Instrument configuration, selection of experimental conditions, the different interfaces used in the system and the current applications of LC×LC–MS systems are described.     

Comprehensive two-dimensional liquid chromatography

Having nearly exhausted the possibilities for generating peak capacity through improvements in column technology, chromatographers are increasingly looking to alternative ways of maximising chromatographic separation. In recent years there has been increasing activity in the field of comprehensive multidimensional separations to meet analysis demands. Comprehensive two-dimensional liquid chromatography (LC×LC) approaches offer high peak capacity which leads to significantly improved analytical performance over single-column liquid chromatography. There are several closely related avenues available for achieving an LC×LC separation and this review pays special attention to the different valve-based interfaces that have been used to comprehensively couple the first and second dimension columns in LC×LC systems. A brief discussion of column choices for selected applications and the conditions employed is also presented.     

基于捕集柱阵列的制备型二维液相色谱纯化烟草中的4个组分

二维液相色谱(2D-LC)因具有较高的峰容量,在复杂样品的分离分析中获得了广泛的关注。然而,制备型2D-LC以纯化高纯单体为目标,在方法开发和设备构成等方面与分析型2D-LC有较大的不同,目前尚未得到充分的开发,在大规模的制备纯化中应用较少。本文以一套制备液相色谱模块为分离系统,以稀释泵、切换阀和捕集柱阵列为接口,构建了新型的制备型2D-LC系统,旨在规模化纯化多个活性成分。以烟叶中可以用作医药原料的烟碱、绿原酸、芦丁和茄尼醇等组分为目标物,考察了不同类型填料对样品的捕集效率、过载条件下的色谱保留行为等,优化了制备色谱条件。进而利用在线2D-LC系统实现了烟叶提取物的纯化,通过一次运行获得了4个高纯化合物。该系统具有中压色谱纯化成本低、系统在线运行自动化程度高、稳定性好及容易放大等优点。烟叶中活性化学成分的回收利用对促进烟草行业的发展及带动地方农业经济开发具有重大的意义。     

Molecular interconversion behaviour in comprehensive two-dimensional gas chromatography

Comprehensive two-dimensional gas chromatography (GC x GC) is shown to provide information on dynamic molecular behaviour (interconversion), with the interconversion process occurring on both columns in the coupled-column experiment. The experiment requires suitable adjustment of both experimental conditions and relative dimensions of each of the columns. In this case, a longer column than normally employed in GC x GC allows sufficient retention duration on the second column, which permits the typical plateau-shape recognised for the interconversion process to be observed. The extent of interconversion depends on prevailing temperature, retention time, and the phase type. Polyethylene glycol-based phases were found to result in high interconversion kinetics, although terephthalic acid-terminated polyethylene glycol had a lesser extent of interconversion. Much less interconversion was seen for phenyl-methylpolysiloxane and cyclodextrin phases. This suggests that for the oximes, interconversion largely occurs in the stationary phase. Examples of different extents of interconversion in both dimensions are shown, including peak coalescence on the first column with little interconversion on the second column.     

Sheath liquid interface for the coupling of normal-phase liquid chromatography with electrospray mass spectrometry and its application to the analysis of neoflavonoids

A novel interface that allows normal-phase liquid chromatography to be coupled with electrospray ionization (ESI) is reported. A make-up solution of 60 mM ammonium acetate in methanol, infused at a 5 microl min(-1) flow-rate at the tip of the electrospray probe, provides a sheath liquid which is poorly miscible with the chromatographic effluent, but promotes efficient ionization of the targeted analytes. Protonated molecules generated in the ESI source were subjected to tandem mass spectrometric experiments in a triple-quadrupole mass spectrometer. The main fragmentation reactions were characterized for each analyte and specific mass spectral transitions were used to acquire chromatographic data in the multiple reaction monitoring detection mode. Results obtained during optimization of the sheath liquid composition and flow-rate suggest that the electrospray process was mainly under the control of the make-up solution, and that it forms an external charged layer around a neutral chromatographic mobile phase core. This sheath liquid interface was implemented for the analysis of some neoflavonoid compounds and its performance was evaluated. Limits of detection were established for calophillolide, inophyllum B, inophyllum P and inophyllum C at 100, 25, 15 and 100 ng ml(-1), respectively.