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Showing 1 to 20 of 43 for “"supercritical fluid chromatography"”.
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Capillary supercritical fluid chromatography
… of a gas chromatograph for capillary supercritical fluid was demonstrated. The resulting instrument was used to characterize the performance of capillary columns manufactured specifically for SFC applications. The columns were tested for inertness, efficiency, and immobilization before …
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Supercritical fluid chromatography - mass spectrometry
High performance liquid chromatography (HPLC) is the most widely used<br/>separation technique within the pharmaceutical industry. Due to the growing need for<br/>high speed and high quality separations other techniques, such as supercritical fluid<br/>chromatography (SFC), are now being …
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Adiabatic Packed Column Supercritical Fluid Chromatography
A well-known problem in supercritical fluid chromatography is the drastic decrease in chromatographic performance at temperatures above 40 C and outlet pressures below 120 bar. This phenomenon has been attributed to isenthalpic expansion and cooling of the mobile phase and poor heat transport under …
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Supercritical Fluid Chromatography of Ionic Compounds
… the elution of ionic analytes via packed column supercritical fluid chromatography (SFC). Firstly, we focused on the elution of sodium arylsulfonate analytes by using various ionic additives, such as lithium acetate, ammonium acetate, tetramethylammonium acetate, tetrabutylammonium acetate, and …
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Analysis of polar compounds by supercritical fluid chromatography
The analysis of polar compounds has been studied by SFC using 100% CO₂ or methanol modified CO₂ as the mobile phase. Both microbore packed and capillary columns are employed to separate the mixtures of steroids and agricultural compounds of various chemical classes such as amides, sulfonamides and …
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Novel Switchable Stationary Phase Methods For Supercritical Fluid Chromatography
In the first part of this thesis, a supercritical fluid chromatography-flame ionization detection (SFC-FID) system employing a modified water stationary phase was investigated for the analysis of organic bases. The method uses a stainless steel capillary column coated with water containing NH4OH, …
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Supercritical Fluid Chromatography with Chemiluminescent Nitrogen and Sulfur Detection
The need for sensitive and selective detectors in supercritical fluid chromatography (SFC) is particularly evident since SFC can be used to analyze classes of compounds that are not readily amenable to either gas chromatography (GC) or liquid chromatography (LC). These compounds include species …
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Supercritical fluid chromatography of nitrogen-containing compounds on packed columns
… compounds has been investigated via supercritical CO₂ and 1% methanol modified CO₂. Packed columns with the following stationary phases were employed: silica, octadecyl (C₁₈), propylamino (NH₂), and polystyrene-divinyl benzene (PRP). Without modifier the range of basicities which …
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Evaluation of sulfur hexafluoride as a mobile phase for supercritical fluid chromatography
The scope of supercritical fluid chromatography continues to enlarge. The use of open tublar and packed columns, nearly universal detectors and the introduction of new mobile phases make it more important. In this work sulfur hexafluoride is evaluated as a mobile phase for supercritical fluid …
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Investigation of mass spectrometric interfaces for supercritical fluid chromatography and liquid chromatography
… of the particle beam interface (PB) coupled to supercritical fluid chromatography (SFC) and mass spectrometry (MS) were assessed with pure and methanol-modified CO₂. Factors which affect the nebulization and the subsequent desolvation of the droplets were assessed. The quantitative performance …
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Analysis of Alcohol and Alkylphenol Polyethers via Packed Column Supercritical Fluid Chromatography
… methods for non-ionic surfactants utilizing supercritical fluid chromatography (SFC) under mild instrument operating conditions. The aryl group present in APEOs allowed ultraviolet (UV) detection, with an equal molar response for oligomers, allowing average molar oligomer values to be …
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Characterization and optimization of supercritical fluid chromatography with on-line Fourier transform infrared detection
Supercritical fluid chromatography (SFC) has been gaining much exposure over recent years. The characteristics inherent to SFC give it capabilities in separating nonvolatile, thermally labile compounds inseparable by GC, and with greater efficiency per unit time than HPLC. As in the past with the …
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Deactivation and preparation of fused silica open tubular columns for gas and supercritical fluid chromatography
… easily cross-linked, and suitable for use in supercritical fluid chromatography.
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Impact of modified carbon dioxide mobile phases on detection on packed-column supercritical fluid chromatography
The advantages of supercritical fluid chromatography (SFC) and supercritical fluid extraction (SFE) which utilize supercritical fluids (SF) as the mobile phase are being realized by the scientific community. SF are more advantageous than traditionally used organic solvents because SF exhibits the …
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Contributions to method development in capillary electrophoresis and supercritical fluid chromatography for the analysis of pharmaceutical compounds
… látek kapilární elektroforézou a superkritickou fluidní chromatografií Cieľom predloženej dizertačnej práce je skúmanie nových spôsobov vývoja separačných metód pre analýzu štruktúrne podobných farmaceutických látok. Ako analytické separačné metódy boli použité kapilárna elektroforéza (CE) a …
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Quantitative Analysis of Additives in Low Density Polyethylene Using On-line Supercritical Fluid Extraction /Supercritical Fluid Chromatography
… lower than 90%. In recent years, analysis with supercritical fluids (SFs) has emerged as an alternative analytical technique because SFs afford higher diffusivity and lower viscosity. In this research, an on-line Supercritical Fluid Extraction (SFE)/Supercritical Fluid Chromatography (SFC) …
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Measuring Kinetic Performance of Monolithic and Fused-Core Columns Using Packed-Capillary Liquid-, Ultrahigh-Performance- and Supercritical Fluid Chromatography
… liquid (isocratic and gradient elution) and supercritical fluid (isobaric elution) chromatography. The goal of this study is to determine which silica substrate (fused-core, monolithic) is more suitable for high efficiency and speed in packed-capillary liquid and ultrahigh-pressure liquid …
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Aspects of the microwave induced plasma as an element selective detector for supercritical fluid chromatography and supercritical fluid extraction
The introduction of supercritical CO₂ at packed column supercritical fluid chromatography (SFC) flow rates is shown to significantly affect the excitation characteristics of a helium microwave induced plasma (He MIP). In this work, the influence of CO₂ on specific atomic and ionic transitions of …
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A method for direct coupling of supercritical fluid extraction and supercritical fluid chromatography with application to the analysis of nonvolatile coal derived products
In recent years supercritical fluid chromatography has gained attention as an alternative technique to high performance liquid chromatography for the analyses of nonvolatile or thermally labile compounds, whose analysis with gas chromatography is impossible. The work presented here demonstrates a …
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