Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 24 for “"capillary columns"”.
-
Packed capillary columns for liquid chromatography
The advantages and disadvantages of packed capillary columns for high performance liquid chromatography are examined. Historically, the advantages are smaller sample and phase consumption, enhancement in sensitivity, easy column synthesis, higher obtainable efficiency, and easier interfacing to …
-
Comparison of packed and wide-bore, open-tubular gas chromatographic columns
Wide-bore, fused-silica capillary columns can be an excellent replacement for packed columns in many cases. They can provide higher surface inertness and thermal stability, as well as higher efficiency or speed of analysis. Wide-bore, open-tubular (WBOT) columns with thick films have higher sample …
-
Analysis of polar compounds by supercritical fluid chromatography
… 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 ureas. The highly deactivated and crosslinked stationary phases used for both packed and …
-
The separation of diastereoisomers by gas-liquid chromatography
… and a variety of stationary phases was used. Capillary columns were used for chromatography of series 1 and 2 whereas packed columns were used for series 3 to 5. It was found that for all of the above series nearly all of th compounds could be separated into diastereoisomers. The separability …
-
Capillary supercritical fluid chromatography
The modification 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 …
-
Spectroscopic Study of Compressible Mobile Phase and Stationary Phase Behavior in Chromatography
… speed and efficiency, especially in packed columns. This work describes on-column density measurement of CO2, a common carrier fluid for SFC and SGC, in packed capillary columns using Raman microspectroscopy. On-column detection by laser-induced fluorescence is used to observe the effect of …
-
Characterization of resins in alternative fuel mixtures
… to exist in liquid fuels, on two fused silica capillary columns (Carbowax 20 M and SE-54), and by mass spectral interpretation. GC/MS results indicate that "resins" are mainly composed of weakly acidic (phenols, indanols, naphthols), mildly basic (benzoquinolines, chloroanilines, etc.), …
-
GLYCOPEPTIDE ANALYSIS OF HIV-1 ENVELOPE PROTEIN USING HPLC/ESI-FTICR MS AND MALDI-TOF MS WITH ASIALOFETUIN ENRICHMENT AND SEPARATION TECHNIQUES
… the separation efficiencies of three various capillary columns. Specifically the separation of glycopeptides from a peptide mixture was conducted on the three columns in order to determine which platform would optimize the separation of N-linked HIV glycopeptides from a peptide mixture.
-
MEMS-Based Micro Gas Chromatography: Design, Fabrication and Characterization
… performance MEMS-based micro gas chromatography columns having wide range of applications in the pharmaceutical industry, environmental monitoring, petroleum distillation, clinical chemistry, and food processing. The first part of this work describes different approaches to achieve …
-
Optimization of capillary GC/FTIR for complex sample analysis
Optimization of capillary gas chromatography-Fourier Transform Infrared (GC-FTIR) spectrometry has been accomplished by studying various columns, lightpipe designs, FTIR detectors and spectroscopic parameters. For adequate separation of complex samples the efficiency of WCOT (Wall Coated Open …
-
Investigation of column and instrumental parameters for fast gas chromatography analysis
… than js actually being spent on the analysis. Capillary columns are known to be very efficient due to the long lengths and thin stationary phase films. However, analysis can be done much faster if shorter column lengths and thinner stationary phases are used because the retention time is a …
-
Application of an Ionic Liquid Column to the Analysis of Flavor and Fragrance Ingredients
… glycol/wax) stationary phase gas chromatography columns pose challenges for flavor and fragrance analysis particularly in regards to thermal instability at high temperatures, degradation when exposed to water, unchanging selectivity, and relatively short shelf lives. Recently, capillary columns …
-
Pressure-driven and electroosmotically-driven liquid chromatographic separations in packed fused silica capillaries
… manufacture of 2mm ID analytical and suppressor columns and a micro-conductivity cell. The quality of the columns and detector cell are evaluated by the separation of a test mixture and the calculation of peak variance contribution of the detector cell. The use of readily available analytical …
-
Selectivity and detection in capillary electrophoresis
… of the selectivity and detection limitations in capillary electrophoresis. A more practical design of an electrochemical detector is introduced with simultaneous on-line UV detection¹, for the selective detection of a number of pungent and neurological compounds, the piperines and the …
-
THE DETERMINATION OF TRACE METALS BY CAPILLARY ELECTROPHORESIS
The development of a capillary electrophoresis (CE) method for the determination of inorganic and organo mercury species as their dithizone sulphonate (DzS) complexes using coated capillary columns is described. The complexes were pre-formed before injection and detection was by direct measurement …
-
The gas chromatographic separation properties of azulene and the synthesis and characterization of bulky bis-pyrazolylpyridine metal-ligand complexes.
… azulene derivative were synthesized, coated onto capillary columns, and evaluated. To compare the effects of increased polarity vs the effects of polarizability, isomeric naphthalene analogues were also prepared, coated, and evaluated. The coated phases displayed efficiencies up to 2700 plates/m. …
-
Physical and chemical changes in porcine gastric mucus in the normal and ulcerated status
… times, relative to standards, on both packed and capillary columns. The most striking changes indicated by the GLC analyses were a decrease in the fucose content of the mucins from the normal to the ulcerated states and an increase in the proportion of N-acetylglucosamine in mucins from …
-
Supercritical fluid chromatography of nitrogen-containing compounds on packed columns
… 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 could be eluted increased in the order of silica < PRP < …
-
STUDIES OF TIN OXIDE GAS SENSORS FOR GAS CHROMATOGRAPHIC DETECTION
… aldehydes, ketones and some Cs hydrocarbons. Capillary columns were used in this investigation and it was noted that they had potentially wider application than packed columns due to the use of an inert carrier with an air make-up flow to the detector. This replaced the air carrier gas used …
-
The Investigation and Application of Alternative Strategies for LC/MS based Bioanalytical Research
… compared to 10219 plates for standard silica capillary columns. Gradient performance utilizing a diverse mix of compounds yielded a peak capacity of 55 as the average peak widths for all analytes was 0.11 minutes for a 6 minute separation. Resolution of the probe pharmaceutical alprazolam and …
Page 1 of 2