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Hübner J Nguyen A Turcu F Melchior D Kling HW Gäb S Schmitz OJ 《Analytical and bioanalytical chemistry》2006,384(1):259-264
Pulsed amperometric detection following micellar electrokinetic chromatography has been applied successfully to the direct
detection of alkyl polyglucosides (APGs) in shampoos and other industrial products without prior conversion to highly absorbing
or fluorescing derivatives. For electrochemical detection, it is necessary to dissociate the hydroxyl groups of the APGs.
Thus, we used 0.1 M NaOH in the outlet vial to dissociate the APGs. The main problems associated with the combination of electrochemical
detection and capillary electrophoresis are the need to isolate the detector from the electric field used in the capillary
electrophoresis separation and the difficulty of aligning the working electrode with the end of the capillary. To overcome
these problems, a simple capillary-electrode holder was constructed. This holder automatically aligns the capillary and the
electrode in a wall-jet configuration without the aid of micropositioners and facilitates the replacement of electrodes and
capillaries without reconstruction of the entire capillary/electrode setup. Special microcylindrical gold electrodes have
been produced by sealing 300-μm-diameter gold wire into borosilicate-glass capillaries. 相似文献
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Reactions of neutral amino phosphine compounds HL1-3 with rare earth metal tris(alkyl)s, Ln(CH2SiMe3)3(THF)2, afforded a new family of organolanthanide complexes, the molecular structures of which are strongly dependent on the ligand framework. Alkane elimination reactions between 2-(CH3NH)-C6H4P(Ph)2 (HL1) and Lu(CH2SiMe3)3(THF)2 at room temperature for 3 h generated mono(alkyl) complex (L1)2Lu(CH2SiMe3)(THF) (1). Similarly, treatment of 2-(C6H5CH2NH)-C6H4P(Ph)2 (HL2) with Lu(CH2SiMe3)3(THF)2 afforded (L2)2Lu(CH2SiMe3)(THF) (2), selectively, which gradually deproportionated to a homoleptic complex (L2)3Lu (3) at room temperature within a week. Strikingly, under the same condition, 2-(2,6-Me2C6H3NH)-C6H4P(Ph)2 (HL3) swiftly reacted with Ln(CH2SiMe3)3(THF)2 at room temperature for 3 h to yield the corresponding lanthanide bis(alkyl) complexes L3Ln(CH2SiMe3)2(THF)n (4a: Ln = Y, n = 2; 4b: Ln = Sc, n = 1; 4c: Ln = Lu, n = 1; 4d: Ln = Yb, n = 1; 4e: Ln = Tm, n = 1) in high yields. All complexes have been well defined and the molecular structures of complexes 1, 2, 3 and 4b-e were confirmed by X-ray diffraction analysis. The scandium bis(alkyl) complex activated by AlEt3 and [Ph3C][B(C6F5)4], was able to catalyze the polymerization of ethylene to afford linear polyethylene. 相似文献
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Summary A simple and general method for the determination of both C1−C10 alkyl sulfonates and alkyl carboxylates using the same basic methodology, based on High Performance ion Chromatography, using
relatively simple eluent systems allowing fast analysis with both high sensitivity and accuracy is presented. 相似文献
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Retention behaviors of alkyl phosophates were studied on a series of ionic liquid gas chromatography columns. The selectivity of the IL columns for alkyl phosphates were compared with a 5% phenyl column as a route to evaluating the potential use of IL columns in the analysis of alkyl phosphates in petroleum samples in both one- and multi-dimensional GC. Most interestingly, we demonstrate for the first time the dependence of elution order on separation temperature for members of a homologous series of compounds. At low temperatures it was found that trihexyl phosphate eluted before trioctyl phosphate, while at higher temperatures this pattern was reversed. 相似文献
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碳五馏分中微量阻聚剂二乙基羟胺的气相色谱测定法 总被引:2,自引:0,他引:2
提出采用HP-l毛细管色谱柱测定碳五馏分中微量阻聚剂二乙基羟胺组分的气相色谱方法。在本文提出的条件下,二乙基羟胺与其他组分分离良好,检出限低于20mg/kg,相对标准偏差为3.86%,结果准确可靠,方法满足控制分析的要求。 相似文献
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Matsson MK Kronberg B Claesson PM 《Langmuir : the ACS journal of surfaces and colloids》2004,20(10):4051-4058
The equilibrium adsorption behavior of two n-alkyl-beta-D-glucosides (octyl (C8G1) and decyl (C10G1)) and four n-alkyl-beta-D-maltosides (octyl (C8G2), decyl (C10G2), dodecyl (C12G2), and tetradecyl (C14G2)) from aqueous solution on a titania surface, as measured by ellipsometry, has been investigated. The main focus has been on the effect of changes in the alkyl chain length and headgroup polymerization, but a comparison with their adsorption on the silica/water and air/water interfaces is also presented. Some comparison with the corresponding adsorption of ethylene oxide surfactants, in particular C10E6 and C12E6, is given as well. For all alkyl polyglucosides, the maximum adsorbed amount on titania is reached slightly below the critical micelle concentration (cmc), where it levels off to a plateau and the amount adsorbed corresponds roughly to a bilayer. However, there is no evidence that this is the actual conformation of the surfactant assemblies on the surface, but the surfactants could also be arranged in a micellar network. On hydrophilic silica, the adsorbed amount is a magnitude lower than on titania, corresponding roughly to a layer of surfactants lying flat on the surface. A change in the alkyl chain length does not result in any change in the plateau molar adsorbed amount at equilibrium; however, the isotherm slope for the alkyl maltosides increases with increasing chain length. Headgroup polymerization on the other hand affects the adsorbed amount. The alkyl glucosides start adsorbing at lower bulk concentrations than the maltosides and equilibrate at higher adsorbed amounts above the cmc. When compared with the ethylene oxide (EO) surfactants, it is confirmed that the EO surfactants hardly adsorb on titania, since the measured changes in the ellipsometric angles are within the noise level. They do, however, adsorb strongly on silica. 相似文献