毛细管离子色谱进展

从毛细管离子色谱柱制备和毛细管离子色谱仪器研制两方面评述了毛细管离子色谱目前的发展状况。毛细管离子色谱柱包括开管离子色谱柱，毛细管颗粒填充离子色谱柱以及最近几年发展起来的整体毛细管离子色谱柱。对毛细管离子色谱仪的总结包括微流量泵、小体积进样器、适合毛细管离子色谱系统的小体积抑制器、电导和光学检测器等。     

一种简单的毛细管色谱柱电加热装置的制作方法及其在液相色谱-质谱联用系统中的应用

为了实现蛋白质组的深度覆盖,特别是低丰度蛋白质的定性鉴定和定量分析,目前常用的方法是采用更长或装填更小粒径填料的毛细管色谱柱,但因此带来的问题是色谱柱反向柱压显著升高。针对以上问题发展了一种简单的毛细管色谱柱电加热装置制作方法,并将该装置安装于液相色谱-质谱联用系统,分别以牛血清白蛋白(BSA)酶切肽段混合物和酵母蛋白(yeast)酶切肽段混合物为样品,从柱压和柱效两方面对该装置的性能进行了评价。实验结果表明,所制作的毛细管柱电加热装置安装在装填粒径为3 μm反相色谱填料的毛细管柱上,在最佳电流(100 mA)下对BSA及yeast酶切肽段混合物进行分离时的柱压比不加电流时的柱压降低至少50%,柱效略有升高。这说明所制作的毛细管色谱柱电加热装置能显著降低柱压,为在较低的柱压条件下选择更小粒径色谱颗粒填料的毛细管色谱柱提供了一种有效的方法。     

一种多通道匀浆装填毛细管色谱柱的新装置及应用

针对目前毛细管色谱柱装柱效率低、不同批次装填的毛细管色谱柱之间性能差异大的问题,我们发展了一种多通道匀浆装填毛细管色谱柱的新装置。该装置以液相色谱泵提供压力、采用磁力搅拌保持匀浆液均匀分散,一次可装填多达6根毛细管色谱柱。以牛血清白蛋白(BSA)的胰蛋白酶酶切肽段混合物为样本,选择峰容量、蛋白覆盖率、3个特定离子的保留时间以及毛细管色谱柱柱压为指标,在毛细管液相色谱-质谱联用系统上对装填的反相毛细管色谱柱的性能进行了评价。分别考察了一次装填的6根毛细管色谱柱、两次装填的12根毛细管色谱柱以及一次装填1根与一次装填6根毛细管色谱柱的性能及稳定性。实验结果表明:同一批次装填的6根毛细管色谱柱的性能相近;不同批次装填的12根毛细管色谱柱的峰容量和覆盖率没有明显的区别,但保留时间和毛细管色谱柱柱压的稳定性较差;一次装填1根和一次装填6根毛细管色谱柱柱性能的稳定性与两次分别装填6根毛细管色谱柱的稳定性相近,即采用本装置可显著提高毛细管色谱柱的装填效率且每次装填毛细管色谱柱的数量不会对柱性能产生影响。     

Stimultaneous quantitative analysis using dual capillary columns of different polarities

Complex organic mixtures, such as coal liquefaction and oil shale products and by-products, are comprised of hundreds or thousands of individual components. State-of-the-art high resolution gas chromatography does not always provide sufficient resolution to allow accurate quantitation or identification of many compounds of interest. The concept of dual capillary column chromatography combines the different resolving characteristics of two capillary columns coated with different stationary phases into a single chromatographic run. In this approach, both columns are connected to the same injection port. Analysis of complex mixtures in this fashion can confirm the identification and quantitation of components on two columns of different polarity with little increased analysis time, can provide a means of obtaining quantitative data for individual components which are known to coelute on any one column, and can alert one to unknown coelution problems that would be undetected by gas chromatographic analysis on a single capillary column. Simultaneous dual column analysis was applied to three samples, the neutral polycyclic aromatic hydrocarbon (PAH) fraction of a Solvent Refined Coal-II (SRC-II) heavy distillate, the nitrogen-containing polycyclic aromatic compound (N-PAC) fraction of an SRC-II heavy distillate, and the basic fraction from a shale oil process water. Fused silica capillary columns coated with SE-54 and Durawax 3 were used for the analyses of the heavy distillate, while SE-54 an Carbowax 20M capillary columns were used for the analysis of the process water.     

A Simple Design to Realize Micro-column Separation by Conventional Analytical HPLC

The conventional analytical HPLC was successfully developed for micro‐column separation by using a simple eluate splitting system, self‐preparation of packing column and on‐capillary column detector in our laboratory. Porous inlet frit in fused silica capillary was rapidly prepared by sintering stainless steel powders under 500 meshes for about 20 s. The use of such frits or metal meshes in capillary to retain C₁₈ particles of chromatographic packing was demonstrated to be stable and specially robust with continuous packing and long chromatographic runs. Furthermore, the chromatographic behavior was detailedly evaluated by changing the flow rate and the percentage of mobile phase using the prepared capillary column. Under the optimal experimental conditions, baseline separation of the model analytes including thiourea, benzene, toluene, ethylbenzene was obtained with a high column efficiency near 70000N (plates/m) by the developed capillary‐HPLC.     

带喷头混合型毛细管色谱柱的制备及其在蛋白质组分离分析中的应用

本研究制备了一种应用于液-质联用（LC-MS）系统中的带喷头混合型毛细管色谱柱．用标准蛋白和酵母蛋白胰蛋白酶酶切溶液考察了其在LC—MS中的离子化效率、毛细管色谱柱分离性能和寿命,并与直接填充型毛细管色谱柱的色谱性能进行比较,未见显著性差异．将制备的带喷头混合型毛细管色谱柱应用于鼠肝蛋白组的分析,在假阳性率为1％的条件下鉴定到1262个肽段,归属于513个蛋白簇．通过对鉴定蛋白质理化性能的统计分析,其等电点和分子量分布高于一般两维凝胶电泳的范围．实验结果还表明该混合型毛细管色谱柱在肽段的理化性能上没有偏性,可以广泛应用于蛋白质组学的研究中．     

Single fiber-in-capillary annular column for gas chromatographic separation

A method for preparation of a stationary phase-adjustable column with in-column stationary phase-coated fused-silica fiber annular column was successfully developed. The surface of a 0.12 mm o.d. bare optical fiber was first coated with a stationary phase and then inserted into a fused-silica capillary (non-coated or coated) as an annular column for gas chromatographic study. The optical fiber and capillary were coated with polydimethylsiloxane (SE-30) and polyethylene glycol 20M (PEG-20M) as nonpolar and polar stationary phases, respectively. Among the investigated annular and open tubular columns, the PEG-20M-coated fiber-in-PEG-20M-coated capillary annular column showed the highest column efficiency with a minimum plate height of 0.35 mm and an optimum gas velocity of 25 cm/s. When a SE-30/PEG-20M-coated fiber-in-uncoated capillary annular column was applied to separate a 9-component complex mixture, the total analysis time was 5.3 min and the column length was 12 m. By contrast, when a SE-30-coated fiber-in-PEG-20M-coated capillary annular column was used to separate the same 9-component mixture, the analysis time was reduced to 3.5 min and the column length was shortened by half to 6 m. Our results show that the stationary phase-coated fiber-in-stationary phase-coated capillary annular column is a better choice for gas chromatographic separation as it is more efficient and flexible. In addition, the proposed annular column design provides flexibility in using two or even more types of stationary phases to achieve optimal analytical separation.     

Capillary ion chromatography of inorganic anions on octadecyl silica monolith modified with an amphoteric surfactant

A reversed-phase monolithic silica based capillary column (Onyx C(18), 150 mm x 0.1 mm) was modified with the amphoteric surfactant, N-dodecyl-N,N-(dimethylammonio)undecanoate (DDMAU) and evaluated for the separation and determination of inorganic anions using on-column capacitively coupled contactless conductivity detection (C(4)D). The chromatographic performance of the column was evaluated and under optimal conditions separation efficiencies of 56,200 plates per meter or 7025 plates per column (at detection point) were observed (for iodide). Direct plumbing of the capillary column to the micro-injector and on-column detection eliminated extra-column band broadening, thus allowing accurate analysis of van Deemter curves obtained for the monolithic capillary column. The calculated value for the C-term in the obtained van Deemter curve was between 3 and 4 ms for inorganic anions, allowing for the utilisation of relatively high flow rates without significant losses in efficiency. The performance of the C(4)D detector was investigated and compared for detection on an open tubular capillary column and on the modified monolithic silica capillary column. The on-column detection approach did not result in any significant decrease in peak sensitivity for the monolith compared to responses recorded for open tubular capillary columns, and in addition meant the system could be applied to rapid separations by simple variation in apparent column length. The proposed chromatographic system allowed for detection of common anions at sub-ppm level with a 10 nL injection volume. Additionally, on-column detection allowed visualisation of the development of the separation at any point in time and evaluation of the longitudinal uniformity of the ion-exchange coating.     

溶胶-凝胶毛细管气相色谱柱热稳定性和柱寿命的观测

溶胶-凝胶色谱柱有很强的热稳定性,在升温过程中,固定相的流失很低,且有很长的柱寿命与之相比,静态法涂渍及用自由基引发交联反应使固定相固载化的传统色谱柱在柱温远低于溶胶-凝胶柱使川温度的条件下,固定相明显流失且柱寿命短。     

基于石墨化炭黑预涂覆技术的色谱柱制备和性能评价

采用石墨化炭黑(GCB)预涂覆技术对白酒分析专用色谱柱(LZP-930)的制备方法进行了优化,详细考察了所制备的色谱柱(LZP-930G)的性能参数,并对LZP-930G色谱柱的保留行为进行了评价,探讨了GCB对LZP-930G色谱柱性能的影响。研究发现,LZP-930G色谱柱的柱效、惰性、稳定性和极性均得到了明显提高,从而改善了酸类和醇类组分的分离选择性和色谱峰峰形,实现了白酒中53种易挥发和半挥发性微量组分的同时分离,且各组分的保留时间和峰面积的相对标准偏差分别小于0.63%和4.51%(n=5)。表明GCB预涂覆技术能够用于高性能白酒分析色谱柱的制备方法。     

Direct diagnosis of tuberculosis by computer assisted pattern recognition gas chromatographic analysis of sputum

Chemical detection of tuberculosis (TB) products in sputum was attempted by using gas chromatographic analysis in conjunction with different pattern recognition computer models. For the chromatographic separations, we used a 2 mm x 1.8 m packed column and a 0.25 mm x 30 m fused silica capillary column to analyse the methylated glycosides and fatty acid methyl ester derivatives. Three computer pattern recognition methods were applied: error score, TB score and discriminant analysis. These methods predicted the presence of active TB most often in sputa of active TB patients and less so in those from inactive, suspected and non-TB patients, in that order. Although the best true positive of 75% was obtained from the TB score method and best true negative of 98% from discriminant analysis, the accompanying false positive and false negative results (36% and 50%, respectively) were unacceptable. The use of capillary column or fatty acid methyl ester derivatives of the samples did not improve on the predictive values of chromatograms obtained from the packed column on trimethylsilylglycosidic derivatives. Additional work is needed before this method can have a direct clinical application.     

Enhancement of Signal-to-Noise Ratios in Capillary Gas Chromatography by Using a Longitudinally Modulated Cryogenic System

A Longitudinally Modulated Cryogenic System (LMCS) was evaluated for its use in detection enhancement in capillary gas chromatography. The mechanism for chromatographic re-elution for the LMCS is substantially different to other cryogenic devices. The cooled region of the capillary column in which chromatographic bands may be focused is heated by the surrounding oven temperature either by moving the trap along the column, or by moving the column out of the trap. By continually modulating the LMCS at the detector end of the capillary column, signal-to-noise ratios of routine chromatograms can be readily increased by a factor of ten, thus enhancing chromatographic detection. Base widths of peaks, which are often about 2–3 s or more can be easily reduced to 0.3 s when the LMCS is employed in the detection enhancement mode, thus offering a simple avenue to improved peak height sensitivity in capillary gas chromatography.     

毛细管气相色谱法测定三聚氰酸三烯丙酯中丙烯醇的含量

建立了毛细管气相色谱测定三聚氰酸三烯丙酯中丙烯醇含量的方法．采用25m×0．32mm×0．25μm FFAP毛细管柱分离,氢火焰离子化检测器,内标标准曲线法（正丁醇作内标物）定量．方法简便、快速、准确,测定的相对标准偏差为0．61％～1．97％,平均回收率为97．1％～100．7％．     

Electroosmotic pump‐supported molecularly imprinted monolithic column for capillary chromatographic separation of nitrophenol isomers

In this work, a novel molecularly imprinted polymer (MIP) monolithic column with integrated in‐column electroosmotic pump (EOP) was designed and successfully prepared to facilitate the capillary chromatography with MIP column. A silica‐based EOP was synthesized at the detection end of the MIP monolithic capillary column by so‐gel to provide the hydrodynamic driven force for the capillary chromatography. Because of large surface area and low fluidic resistance of the silica monolith,a strong and steady EOF was generated by silica‐based EOP, indicating that the EOP was quite compatible with MIP capillary column. With the sufficient EOF provided by EOP, the electro‐driven based capillary chromatographic separation of nitrophenol isomers was achieved in 4‐vinylpyridine‐based MIP monolithic capillary, which was originally proved infeasible because of the EOF shortage. No significant influence upon the specific recognition of the MIP was found due to the setting of EOP after the detection window of the column. The influence of experimental parameters on the EOF such as voltage and pH value of running buffer was investigated. The column was also evaluated by capillary liquid chromatographic mode to compare with EOP‐driven capillary chromatography. Higher column efficiency was obtained by EOP‐driven separation with improved peak shape. The results suggested that EOP‐supported technique would be a good way to solve the problem of weak EOF generation in electro‐driven capillary chromatography.     

自制新型毛细管色谱柱分析有机羧酸

将合成的十二迷基苯碘酸三正丁铵盐配成合适体积分数的固定相溶液,用汞塞动态法＾〖１〗涂柱制备成适合直接进样分离羧酸的毛细管气相色谱法。制成的色谱柱具有较佳的性能和较强的选择分离功能,特别是对强极性物质（如羧酸）更突出。较详细地讨论了这类毛细管柱的制备方法,对羧酸的分离以及定量分析,并给出了几个分析实测。     

Fused silica capillary GC separation of alkene halohydrins

The use of a fused silica capillary column for the gas chromatographic analysis of alkene halohydrin positional isomers is described. This method is illustrated with the complete resolution of the positional isomers for propylene bromohydrin, propylene iodohydrin, and allyl bromide bromohydrin. Comparison with the resolution obtained on a packed column is also provided.     

Characterization of high performance glass capillary gas chromatography

Summary High resolution gas chromatography requires the highest performance characteristics of gas chromatographic systems in terms of sampling and sample handling in strumentation, columns, and data handling. This paoper describes high precision computer measurements for characterizing capillary column efficiencies which are within 75% of the theoretical limit of capillary GC. Particular emphasis is given to detailed peak shape analysis, measurement accuracy and reproducibility, and system stability. Using known instrument performance parameters, it is then possible to characterize column performance with high accuracy in a meaningful manner. It is proposed that wall-coated tubular columns be characterized in terms of their chromatographic performance by the following parameters: Trennzahl (separation number), number of theoretical plates/meter, program temperature beseline stability, acid-base ratio, and the coefficient of skewness for 1-octanol. Statistical moments (m2) and hybrid moments are used to describe capillary column chromatographic performance because they may be related to basic physico-chemical column processes. These measurements are very sensitive parameters for characterizing GC columns. Using an online computer-based data system, the limits of capillary GC are shown to be limited by the sampling and injection steps.     

Programmable Temperature Vaporizer (PTV) Applied to the Triglyceride Analysis of Milk Fat

The PTV (Programmable Temperature Vaporizer) is a split/splitless injector which allows the sample to be introduced at a relatively low temperature, thus affording accurate and reproducible sampling. After injection the PTV is rapidly heated to transfer the vaporized components into the capillary column. This type of injector has proved to be an efficient tool for the evaluation of fatty acids, essential oils, and pesticides in food analysis. In this work the suitability of PTV for the analysis of milk fat purity by the Official EU method was evaluated. This method is based on the gas chromatographic determination of triglycerides only according to their total number of carbon atoms followed by the application of formulae deriving from multiple linear regressions. The analysis is currently carried out with a packed column or a short capillary column and an on-column injection system. Several samples of pure milk fat and mixtures of milk fat with foreign fat were analyzed with the same capillary column and by using both PTV and on-column injection systems. The results show that the gas chromatographic profile obtained by PTV is comparable with that obtained by the on-column injector, while repeatability and reproducibility data meet the requirements indicated in the Official Method. Therefore, this study demonstrates that it is possible to use the PTV instead of the on-column injector to determine the purity of milk fat with this method.     

Performance evaluation of long monolithic silica capillary columns in gradient liquid chromatography using peptide mixtures

A systematic study is reported on the performance of long monolithic capillary columns in gradient mode. Using a commercial nano-LC system, reversed-phase peptide separations obtained through UV-detection were conducted. The chromatographic performance, in terms of conditional peak capacity and peak productivity, was investigated for different gradient times (varying between 90 and 1320min) and different column lengths (0.25, 1, 2 and 4m) all originating from a single 4m long column. Peak capacities reaching values up to n=10(3) were measured in case of the 4m long column demonstrating the high potential of these long monoliths for the analysis of complex biological mixtures, amongst others. In addition, it was found that the different column fragments displayed similar flow resistance as well as consistent chromatographic performance in accordance with chromatographic theory indicating that the chromatographic bed of the original 4m long column possessed a structural homogeneity over its entire length.     

Alltech集束毛细管柱和常规毛细管柱的比较

对集束毛细管气相色谱柱的色谱性能,如流速对柱效的影响、柱温对柱效的影响、柱容量等进行了考察,并将其对典型火炸药成分ＤＮＴ,ＴＮＴ的分离与常规毛细管气相色谱柱进行了比较。结果表明,集束毛细管气相色谱柱综合了填充柱与石英毛细管气相色谱柱之优点,弥补了二者的不足,是一种柱容量较大且分离效能好、可以在高载气流速下操作的新型气相色谱柱。