King Saud University

Mohamed Ali Ouladsmane

Zeid Abdullah ALOthman

Ahmed Yacine Badjah Hadj Ahmed

Taieb Aouak

Mohammed Mousa Alshehri

Ahmad Aqel Ifseisi

The method of metered switching for a high-performance liquid chromatography (HPLC) sample injector is a method of controlled switching for a HPLC sample injector to control the amount of the sample being transferred to the HPLC separation column. In a load mode of the HPLC sample injector, a sample to be tested is injected therein until a sample loop is filled. The HPLC sample injector is switched into an injection mode such that a pressurized mobile phase pushes the sample through the sample loop and out of an outlet port. The HPLC sample injector is then switched back into the load mode at a selected time corresponding to a desired volume of the sample to be dispensed from the outlet port. The time-dependent correspondence between a flow rate of the pressurized mobile phase and the desired volume of the sample for the sample loop is already known.

Method of metered switching for a high-performance liquid chromatography sample injector

The method of making a wall-coated open tubular capillary column with a poly benzyl stationary phase is a method of preparing a capillary column for gas chromatography. An inner wall of a fused silica capillary column is cleaned and then rinsed with a sodium hydroxide solution. The fused silica capillary column is flushed with isopropanol to form a pre-treated capillary column, and the pre-treated capillary column is loaded with a mixture of phenyl tri-methoxy silane and alcohol. The loaded pre-treated capillary column is heated to form a treated capillary column, which is then washed. A thin layer of a poly benzyl stationary phase is then coated on the inner wall through condensation polymerization of benzyl chloride monomers with a Lewis acid catalyst in a non-polar solvent.

Method of making a wall-coated open tubular capillary column with a poly benzyl stationary phase

The extraction of benzene from benzene/cyclohexane mixture described herein is a process that removes benzene from a benzene/cyclohexane mixture with high selectivity, resulting in an enriched cyclohexane content in the retentate. The process involves adding an aqueous solution of poloxamer 188 to the benzene/cyclohexane mixture and waiting for the mixture to partition into an organic layer above an aqueous layer. Benzene, being more polar than cyclohexane, is selectively drawn into the aqueous layer. Benzene is then removed from the aqueous layer by pervaporation through a composite PDMS (polydimethylsiloxane)/polystyrene membrane. Cyclohexane is recovered from the retentate by drawing off the organic layer of the retentate by any known method. About 97% of benzene has been removed from a 50-50 wt % mixture by pervaporation in the static mode, and about 99% by pervaporation in the continuous mode.

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Riyadh, Saudi Arabia

Mohamed Ali Ouladsmane