Electrochromatography (that is HPLC where the eluent is driven along the column by electro-osmosis using fields of up to 100 kV m−1) promises plate efficiencies for HPLC which are comparable to those attained in capillary gas chromatography, but this requires that narrow-bore columns can be successfully packed with submicron particles. This paper demonstrates that we have now moved a considerable distance towards this goal. We show (1) that, following theory, there is no evidence of any reduction in electroosmotic velocity in columns packed with particles down to 1.5 μm diameter, (2) that reduced plate heights as low as unity are attainable for unretained solutes using both slurrypacked and drawn-packed columns 30 to 200 μm bore and up to 1 m long when packed with conventional 3 and 5 μm silica gels or with 1.5 μm impermeable silica spheres, (3) that columns driven electrically show higher plate efficiencies than identical columns driven by pressure, and (4) that 100,000 plate HPLC separations can be achieved in relatively short times of 30 minutes using in situ derivatised drawn packed capillaries containing 3 and 5 μm ODS-silica gels.

Electrochromatography in packed tubes using 1.5 to 50 μm silica gels and ODS bonded silica gels

Etude de l'effet du diametre de la colonne sur la performance de la colonne garnie de silice fondue modifiee par le groupement octyl

Preparation and evaluation of packed capillary liquid chromatography columns with inner diameters from 20 to 50 μm

On-column UV absorption detector for open tubular capillary zone electrophoresis

Etude du phenomene d'elargissement de bandes lors de chromatographie electrocinetique. Passage en revue des differentes causes d'elargissement de bandes (diffusion longitudinale, cinetique de sorption-desorption, transfert de masse intermicellaire, influence du gradient de temperature radiale sur la vitesse electrophoretique, dispersion electrophoretique des micelles,…)

Band broadening in electrokinetic chromatography with micellar solutions and open-tubular capillaries

This review considers the technique of thermal lens spectrometry and its applications to chemical measurements in solid, liquid and gaseous phases. Practical applications, theoretical treatments and instrumental developments are considered in terms of their analytical use and potential.

Thermal lens spectrometry. A review

Fused-silica narrow-bore microparticle-packed-column high-performance liquid chromatography

Open Tubular Column LC: Theory and Practice

On-column detection using a fused silica column

A process for packing narrow bore chromatographic columns and the resulting product are provided. A flexible column, preferably of fused silica, of inner diameter less than 500 μm is selected. A slurry is formed in a reservoir from a mobile solvent and particles of specified diameter. For liquid chromatography the particle size ranges from 3 μm to 10 μm; for gas chromatography the particle size ranges from 3 μm to 100 μm. An end restriction is placed in the end of the column to permit the flow of mobile solvent and to restrict the passage of particles out the end of the column. The reservoir is attached to the column and the slurry is caused to flow under pressure into the column. A two-step pressure sequence is used to first set up the bed of particles and then to compress the bed. First, an initial pressure is maintained for an initial period, preferably less than 10 minutes. Next, the pressure is raised from the initial pressure to a maximum pressure and is maintained at the maximum pressure for a second period. The product in either case is a stable, loose packed column having a high plate number per unit length.

Frank J. Yang

Papers

Fused-silica narrow-bore microparticle-packed-column high-performance liquid chromatography

Open Tubular Column LC: Theory and Practice

On-column detection using a fused silica column

Narrow bore micro-particulate column packing process and product

Microbore column HPLC