The preparation of thick-film glass capillary columns

A detailed method for the routine preparation of glass capillary columns is presented. The method consists of coating a glass tube with quartz powder prior to pulling the tube into a capillary. The inner surface of the capillary consists of an even distribution of quartz particles fused to the walls. This surface has been found readily deactivated by standard procedures and ideal for the preparation of thick-film glass capillary columns. The method has been thoroughly tested in two independent laboratories to ensure that the procedures described are reproducible.     

Titantetrafluorid – Eine überraschend einfache Kolumnarstruktur

Titanium Tetrafluoride – a Surprising Simple Column Structure For the first time single crystals of TiF₄ have been obtained by solvothermal decomposition of (O₂)₂Ti₇F₃₀ in anhydrous HF. The colourless, transparent needles crystallize orthorhombic in spacegroup Pnma–D (No. 62) with a = 2 281.1, b = 384.8, c = 956.8 pm, Z = 12. The new type of structure is dominated by isolated columns of corner-linked TiF₆-octahedra.     

Preparation and characterization of Fully stoichiometric SrCoO3 by electrochemical oxidation

A nearly stoichiometric SrCoO₃ phase had been prepared up to now only using high oxygen pressure. A new method for preparing fully stoichiometric SrCoO₃ has been proposed using electrochemical oxidation. Brownmillerite-type SrCoO_2.50 is oxidized into a completely stoichiometric perovskite at a potential of 500 mV for 180 hours at room temperature in alkaline media (1 M KOH). The oxidized phase has a cubic unit cell (a=383.5 pm). It is metallic and, at temperatures below T=280 K, it shows ferromagnetic behavior. The magnetic moment at 0 K is 2.1 μ_B. The physical properties of SrCoO_3.00 have been explained in terms of partial occupancy of a σ*e band.     

Coupling of thermal desorption in modified closeable sampling columns with wide-bore capillary gas chromatography and mass spectrometric detection

In contrast to usability of Curie-point pyrolysis at 700°C directly attached to gas chromatography-mass spectrometry (GC-MS) for determination of organic wood preservatives in waste wood samples the investigation method reported here consists of thermal desorption at temperatures about 260°C in connection with GC-MS for peak identification or GC with flame ionization detection for quantitative analyses. So-called “modified closeable sampling columns” are used as batch-reactor in thermal desorption experiments. Desorbed vapours can be introduced on capillary columns without sample discrimination and without a disturbing lost of resolution. In this manner a lot of individual polycyclic aromatic hydrocarbons were determinated in waste wood samples, especially in railway sleepers.     

Glass capillary gas chromatography of amino acid enantiomers

Glass capillaries coated with Chirasil-Val, a chirally functionalised polysiloxane, are capable in principle of resolving all protein amino-acid enantiomers in a single run and within a short analysis time, thus allowing for example the quantitative amino acid determination by enantiomer labelling. The elution characteristics of the individual amino acids however are also dependent upon the chemical nature of the capillary wall surface, and a surface pretreatment is found to be necessary if all protein amino acids are to be analysed. Of the various methods of pretreatment tested, etching of borosilicate glass with gaseous HCl followed by deposition of colloidal silicic acid is considered to be the most suitable.     

Darstellung und Kristallstruktur von LnAl3Br12 (Ln = La,Ce, Pr,Nd, Sm,Gd) und thermischer Abbau zu LnBr3

Preparation and Crystal Structure of LnAl₃Br₁₂ (Ln = La, Ce, Pr, Nd, Sm, Gd) and Thermal Decomposition to LnBr₃ LnAl₃Br₁₂ (Ln = La, Ce, Pr, Nd, Sm, Gd) was prepared in crystalline form for the first time. The crystal structures of LaAl₃Br₁₂, PrAl₃Br₁₂, and NdAl₃Br₁₂ were determined on single crystals by X-ray methods. The isotypic compounds crystallize with trigonal symmetry, space group P 3₁12, Z = 3. A structural comparison to lanthanoide chloroaluminates of equal composition is given and thermal decomposition of LnAl₃Br₁₂ (Ln = Nd) to the corresponding lanthanoide tribromide is described.     

硝酸钆低水合物的制备及表征

本文用两种方法制得硝酸钆的低水合物Gd(NO_3)_3·5H_2O、Gd(NO_3)_3·3.5H_2O,其中Gd(NO_3)_3·3.5H_2O是文献中尚未报道的 ,给出了它们的M.P.和X-衍射特征值。     

一锅法制备全乙酰吡喃溴代糖

将未保护的吡喃糖与醋酸酐在分子碘的催化下制得全乙酰吡喃糖 ,随后不经分离直接与溴化氢的冰醋酸溶液( 4 5 %)反应得到全乙酰吡喃溴代糖 .这种一锅法制备全乙酰吡喃溴代糖操作方便 ,收率高 ,经济实用且对环境友好     

高效除草剂快杀稗标准物质的制备及表征

从快杀稗工业品出发 ,经活性炭纯化、硅胶柱层析分离制得快杀稗标准物质 ,并进行熔点、高效液相色谱、紫外光谱、元素分析、红外光谱、质谱、核磁共振等方法的表征 ,以高效液相色谱法测得该标准品纯度在99%以上     

X—射线荧光光谱测定甜饮料中微量元素

本文提出了低温蒸干和炭化制样Ｘ－射线荧光分析甜饮料中１６种微量元素的方法，试样在电热板上经低温蒸干，于马旨炉中３００℃炭化３０ｍｉｎ，在液压样品成形机上压制成样片进行测定，所测元素不需用任何基体校正，由微机从校正曲线查得含量，榈分析结果与ＩＣＰ－ＡＥＳ和ＡＡＳ法相吻合。