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F Houdiere

Publications and source records attributed to F Houdiere.

5 recordsLinked to original sources
PubMed2001

Evaluation of ODS-AQ stationary phase for use in capillary electrochromatography.

The aim of this study was to evaluate the applicability of ODS-AQ packing material as a stationary phase in capillary electrochromatography (CEC). The electroosmotic flow created on an ODS-AQ stationary phase was measured at different mobile phase compositions and at different column temperatures. It was observed that the electroosmotic flow generated in the column increased by 50% when the temperature of the system was raised from 20 degrees C to 60 degrees C, while all other conditions were kept constant. The electroosmotic flow produced by the ODS-AQ stationary phase was found to be comparable to the flow generated in a column packed with Nucleosil bare-silica material. In addition, a set of polar compounds (D-lysergic acid diethylamide derivatives) was utilized to determine the influence of temperature and mobile phase composition on their chromatographic behavior on an ODS-AQ stationary phase in a CEC mode. A linear relationship between the solute retention factor and column temperatures was seen over the temperature range studied (20 degrees C to 60 degrees C). A quadratic function was used to describe the changes in the solute retention factors with variation of acetonitrile concentration in the mobile phase.

Chromatography, High Pressure Liquid↗
PubMed2001

Separation of peptides utilizing ultrahigh-temperature micellar electrokinetic chromatography.

The use of ultrahigh column temperatures, up to 110 degrees C, in micellar electrokinetic capillary chromatography was investigated. The number of plates generated per unit time increased from 0.22 to 12.8 plates/s for separations at 15 degrees C and 110 degrees C, respectively. Ultrahigh-temperature micellar electrokinetic capillary chromatography was used for the separation of cyclic undecapeptides (cyclosporins). A minimum resolution of 1.39 was calculated for a critical peak pair at 110 degrees C, which is more than a 50% increase over resolution generated at 40 degrees C. During a run time of more than 90 min at 110 degrees C and at pH 9.3, no sample degradation or solvent boiling was observed.

Acetonitriles↗
PubMed2000

High temperature and temperature programming in capillary electrochromatography.

In electrochromatography, solvent electrophoretic mobility and solute partitioning are temperature dependent processes. If temperature variations are controlled, solute selectivity and analysis times can be tailored. In this study the feasibility of temperature programming in capillary electrochromatography (CEC) was demonstrated using a reversed-phase CEC mode. The outcome of programmed separations was compared with isothermal, isocratic and isorheic (constant flow) separations. The combined effects of column temperature and mobile phase flow-rate changes during the separation run, resulted in up to a 50% reduction in the separation run time, without adversely affecting the quality of separation. For capillary electrochromatography, temperature programming may be a valuable alternative to solvent programming modes because of the great technical difficulties associated with carrying out solvent gradient elution.

Electrophoresis, Capillary↗
PubMed2000

Separation of D-lysergic acid diethylamide derivatives using micellar electrokinetic capillary chromatography.

By adjusting column temperature and applied electric field, a fast separation in micellar electrokinetic capillary chromatography was developed for the separation of D-lysergic acid diethylamide derivatives. A baseline separation of nine derivatives was accomplished with a run time of less than 12 min by utilizing elevated column temperature (60 degrees C) and an applied electric field of 387 V/cm. The number of plates generated per unit time for the separations completed at elevated temperatures was significantly higher when compared to separations at the same applied electric field but at lower temperatures (20 degrees C).

Chromatography, Micellar Electrokinetic Capillary↗