کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9749212 | 1493804 | 2005 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Influence of the pressure on the properties of chromatographic columns
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
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چکیده انگلیسی
The compressibilities of aqueous solutions of methanol or acetonitrile containing 0, 20, 40, 60, 80 and 100% (v/v) organic solvent were measured with a dynamic chromatographic method. The elution volumes of thiourea samples (2âμ L) in these solutions were measured at different average column pressures, adjusted by placing suitable capillary restrictors on-line, after the detector. The reproducibility of the measurements was better than 0.2%. In the range of average pressures studied (10-350âbar), the maximum change in elution volume of thiourea is 1.3% (in pure water) and 4.0% (in pure methanol). This difference is due to the different compressibilities of these pure solvents. For mixtures, the plots of the elution volume of thiourea versus the pressure are convex downward, which is inconsistent with the opposite curvature predicted by the classical Tait model of liquid compressibility. This difference is explained by the variation of the amount of thiourea adsorbed with the pressure. The deconvolution of the two effects, adsorption of thiourea and solvent compressibility, allows a fair and consistent determination of the compressibilities of the methanol-water mixtures. A column packed with non-porous silica particles was also used to determine the compressibility of methanol-water and acetonitrile-water mixtures. A negative deviation by respect to ideal behavior was observed.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Chromatography A - Volume 1070, Issues 1â2, 8 April 2005, Pages 1-12
Journal: Journal of Chromatography A - Volume 1070, Issues 1â2, 8 April 2005, Pages 1-12
نویسندگان
Fabrice Gritti, Georges Guiochon,