Early evolution of gas adsorption chromatography. Part I: Displacement development and the beginnings of elution-type investigations

Summary This two-part article reviews the early evolution of gas-adsorption chromatography, before the advent of partition chromatography. After reporting on the early tests to determine the light hydrocarbon content of natural gas and the methodology described by P.Schuftan, the research activities of S. Claesson and C.S.G. Phillips on displacement-type gas-adsorption chromatography and early work on elution-type analysis by G. Damk?hler, E. Wicke, E. Glueckauf and G. Hesse are discussed. Part II of this review article will be published in the forthcoming issue ofChromatographia.     

The predawn of paper chromatography

Summary The activities of F.F. Runge, F. Goppelsroeder and R.E. Liesegang are outlined. The technique of capillary analysis is described and its shortcomings elaborated. Tswett's use of filter paper to imitate plant tissues is explained and finally, the considerations of Izmailov and Shraiber eventually leading to thin-layer chromatography are summarized.     

Paul Schuftan and the early development of gas-adsorption chromatography

The life and activities of Paul Schuftan, a pioneer in gas-adsorption chromatography are discussed and placed in the context of the early evolution of gas chromatography.     

preparative liquid chromatography: History and trends-supplemental remarks

Summary Supplementing the paper of Geeraert and Verzele published in the November 1978 issue of this journal, the controversy between Tswett and Willstätter on preparative liquid chromatography, as well as the pilotscale applications for the isolation of rare earths and pure hydrocarbons are discussed.     

离线二维反相液相色谱/超临界流体色谱在瓜蒌子分离中的应用

发展了离线二维反相液相色谱/超临界流体色谱(2D RPLC/SFC)分离瓜蒌子的方法。实验在第一维采用反相色谱,按色谱峰收集从瓜蒌子样品中制备得到的12个组分(F_1~F_(12)),并将得到的组分在第二维使用SFC分离。这些组分在RPLC和SFC的分离对比说明,该二维方法具有良好的分离正交性,可至少检测到150个色谱峰,对于解决结构相似物质的分离、微量成分的富集表现出了明显的优势。SFC方法采用了乙醇-正己烷(3∶7,v/v)的混合溶剂作为改性剂,既提供了适当的洗脱能力,也保证了在上样量增加时满足样品溶解的要求。此二维分离体系可放大到制备水平用于化合物的制备,为瓜蒌子化学成分的纯化制备提供技术支持,为其物质基础研究提供参考。     

Exhibition of the first gas chromatographic work of Erika Cremer and Fritz Prior

Summary In November 1995, theDeutsches Museum, the world's largest technical museum, opened a new branch in Bonn, devoted to achievements after 1945. There, the first gas chromatographic system used by Erika Cremer and Fritz Prior, in 1945–47, in Innsbruck, is exhibited. The new display is described and the early activities of Erika Cremer and her students are summarized.     

气-液色谱联合分析煤油共炼产物族组成

建立了一项可以直接分析溶液中焦油和重质油族组成的方法。以高效液相色谱(HPLC)配以气相色谱(GC)完成分析检测。分析了煤油共处理(煤油共炼)中，各种原煤、不同催化剂、不同煤油比及操作条件对产品族组成的影响。     

M. S. Tswett and the 1918 Nobel Prize in Chemistry

Summary The general recognition of M. S. Tswett and his achievements are discussed, with special emphasis to his nomination for the 1918 Nobel Prize in Chemistry.     

Group-type fractionation of petroleum and alternative fuels by column liquid chromatography

The present paper introduces an instrumental procedure based on column liquid chromatography for the total analysis of petroleum heavy ends and similar samples. The procedure avoids the precipitation of asphaltenes and asphaltols. One sequence of eluents fractionates the sample into 8 fractions: 5 non-polar (hydrocarbons), one intermediate (resins), and 2 polar fractions (asphaltenes and asphaltols). Quantitative results from gravimetric measurements and UV-Vis and FTIR spectra of fractions obtained from petroleum heavy ends are presented, as well as those from GC/MS data obtained from one fraction obtained from liquefaction of biomass. The method presented is easy to set up and operate, requires minimum operator attention, is reliable (no precipitation), reproducible, and inexpensive.     

Recent applications of chemometrics in one‐ and two‐dimensional chromatography

The proliferation of increasingly more sophisticated analytical separation systems, often incorporating increasingly more powerful detection techniques, such as high‐resolution mass spectrometry, causes an urgent need for highly efficient data‐analysis and optimization strategies. This is especially true for comprehensive two‐dimensional chromatography applied to the separation of very complex samples. In this contribution, the requirement for chemometric tools is explained and the latest developments in approaches for (pre‐)processing and analyzing data arising from one‐ and two‐dimensional chromatography systems are reviewed. The final part of this review focuses on the application of chemometrics for method development and optimization.     

Size‐exclusion chromatography for the determination of the boiling point distribution of high‐boiling petroleum fractions

The paper describes a new procedure for the determination of boiling point distribution of high‐boiling petroleum fractions using size‐exclusion chromatography with refractive index detection. Thus far, the determination of boiling range distribution by chromatography has been accomplished using simulated distillation with gas chromatography with flame ionization detection. This study revealed that in spite of substantial differences in the separation mechanism and the detection mode, the size‐exclusion chromatography technique yields similar results for the determination of boiling point distribution compared with simulated distillation and novel empty column gas chromatography. The developed procedure using size‐exclusion chromatography has a substantial applicability, especially for the determination of exact final boiling point values for high‐boiling mixtures, for which a standard high‐temperature simulated distillation would have to be used. In this case, the precision of final boiling point determination is low due to the high final temperatures of the gas chromatograph oven and an insufficient thermal stability of both the gas chromatography stationary phase and the sample. Additionally, the use of high‐performance liquid chromatography detectors more sensitive than refractive index detection allows a lower detection limit for high‐molar‐mass aromatic compounds, and thus increases the sensitivity of final boiling point determination.     

Synthesis and upconversion luminescence properties of Yb/Tm-codoped BaSiF6 nanorods

One-dimensional BaSiF₆:Yb³⁺(20%)/Tm³⁺(1.2%) nanorods were synthesized by a facile microemulsion method for the first time. X-ray topographic analysis found that the nanorods have a pure rhombohedral structure. Under 980 nm excitation, bright-blue upconversion luminescence was presented in the nanorods, indicating that BaSiF₆ is a new host material for producing desirable upconversion luminescence.     

Cation analysis by thin-layer chromatography and reflectance spectroscopy : Part II. The determination of copper,nickel and zinc

A method has been developed whereby micro quantities of copper, nickel and zinc resolved on cellulose chromatoplates can be analyzed in situ by means of reflectance spectroscopy. Copper and nickel were determined in the presence of 11 other cations without any interference by employing neocuproine and dimethylglyoxime, respectively, as chromogenic reagents. In the case of zinc, the use of 3,3'-dimethyl-naphthidine was equally successful except in the presence of tin, cadmium and iron. Deviations to be expected when the procedure is employed routinely to determine nickel, copper and zinc, were estimated to be 2.1, 2.8 and 5.6%, respectively.     

Experimental design optimization of the separation of the aromatic compounds in petroleum cuts by supercritical fluid chromatography

A experimental design optimization method is demonstrated for evaluation of the resolution of the performance mixture used in the proposed ASTM test to determine the aromatic content of aviation fuels. The method uses a Doehlert experimental matrix test to optimize the resolution and analysis time by varying the pressure and temperature of the supercritical carbon dioxide mobile phase. The separation between saturated and aromatic compounds was optimized using only seven experiments. With this procedure, the analysis time required for determination of the total aromatic content of more complex samples can be reduced to less than 10 min.     

Synthesis and upconversion luminescence properties of YF3:Yb/Tm octahedral nanocrystals

YF₃:Yb³⁺(20%)/Tm³⁺(2%) octahedral nanocrystals were synthesized by a microemulsion method with NH₄HF₂. Pumped with a 980-nm diode laser, the nanocrystals emitted weak blue and intense ultraviolet light. Especially, unusual ³P₂ → ³H₆ (∼265 nm) and ³P₂ → ³F₄ (∼309 nm) emissions, coming from a five-photon excitation process, were observed. The emissions from ¹D₂ and ¹I₆ were much stronger than those from ¹G₄ and ³H₄. The upconversion mechanism was discussed in detail.     

高效液相色谱法同时测定无骨海鱼中的维生素A、D和E

采用反相高效液相色谱法,以甲醇(49 1)为流动相,对维生素A、D和E混标进行高速紫外扫描,在Nova Pak C18柱上获得分离良好的三维图谱。据此,选择维生素A、D和E各自最大吸收波长325、265和290nm作为检测波长。实验结果表明:无骨海鱼中维生素A、D和E的质量分数分别为0.80、0.17、4.14mg kg,相对标准偏差为3.7%～5.0%。质量浓度0.10～10mg L范围内,维生素A、D、E均呈现良好的线性关系,检出限为0.05～0.62mg L,回收率在90.0%～110%之间。     

A comparison of 2-D chromatography separations using UV and (18)O quantification of proteins in similar proteomes

Proteins present in two mitochondria preparations were separated by 2-D chromatography using the ProteomeLab PF-2D Protein Fractional System, protein fractionation in two dimensions (PF-2D). The proteins in each first-dimension fraction were determined by trypsinization and LC-MS/MS. Chromatography peaks were quantified by UV detection using the "Mapping Tools" software (Beckman). The proteins present in UV detected peaks were trypsinized and identified by automated MS/MS sequencing. Relative amounts of the proteins present in the equivalent peak for each sample were assessed by comparison of the intensities of the constituent peptides and a predicted PF-2D value was calculated from the total ion count (TIC) for each peptide. Relative quantification for (18)O labeled peptides was performed using the ZoomQuant (v1.43b) software [1, 2]. We found that the chromatography peaks detected by UV generally contained several proteins. Using (18)O labeling we determined that in each peak the ratios of the constituent proteins were different. When these ratios were normalized using the TIC to account for abundance, the resulting ratio corresponded to that determined by UV. The predicted value for the PF-2D score corresponded to the observed value for each peak irrespective of the number or proteins detected.     

Supercritical fluid chromatography with post-column addition of supporting electrolyte solution for electrochemical determination of tocopherol and tocotrienol isomers

A supercritical fluid chromatography with electrochemical detection system was developed for the simultaneous determination of tocopherol and tocotrienol isomers. The supercritical fluid chromatography with electrochemical detection system was connected with an additional pump to create a flow path to add a supporting electrolyte solution. The supporting electrolyte solution was mixed with a mobile phase in a post-column fashion, enabling the independent control of the separation and detection. After optimization of the measurement conditions, vitamin E isomers and an internal standard substance (2,2,5,7,8-pentamethyl-6-hydroxychroman) were separated within 30 min using a mixture of supercritical carbon dioxide and methanol (99:1, v/v) as a mobile phase and a cyanopropyl column (4.6 mm inner diameter × 250 mm length, 5 μm). For the electrochemical detection, methanol containing 1.0 mol/L ammonium acetate was used as a supporting electrolyte solution, and the applied potential was set at +0.8 V. This analytical method showed good linearity (5–100 μg/mL) and repeatability (less than 2.5% relative standard deviation, n = 6) and was applicable to the determination of tocopherol and tocotrienol isomers in nutrition supplements.     

Microwave‐assisted extraction coupled with countercurrent chromatography for the rapid preparation of flavonoids from Scutellaria barbata D. Don

As a famous Chinese herb having good inhibitory effects on numerous human cancers both in vitro and in vivo, Scutellaria barbata D. Don attracts extensive attention worldwide. In this work, four flavonoids named scutellarin, baicalin, luteolin, and apigenin were simply and rapidly prepared from S. barbata by microwave‐assisted extraction coupled to countercurrent chromatography. Extraction conditions including irradiation time, extraction temperature, liquid/solid ratio, and microwave power were optimized using an orthogonal array design method. The extract of S. barbata was separated and purified with a two‐phase solvent system composed of hexane/ethyl acetate/methanol/acetic acid/water (1:5:1.5:1:4, v/v/v/v/v) and 4.5 mg of scutellarin, 4.6 mg of baicalin, 1.1 mg of luteolin, 2.1 mg of apigenin were obtained from 2.0 g original sample in a single run. The purities of scutellarin, baicalin, luteolin, and apigenin determined by HPLC were 93.6, 97.3, 97.6, and 98.4%, respectively. The targeted compounds were identified by LC with MS and ¹H NMR spectroscopy. The total time including extraction, separation, and purification was <300 min. Compared to traditional methods, microwave‐assisted extraction coupled to countercurrent chromatography method is more simple and rapid for the extraction, separation, and purification of flavonoid compounds from natural products.