Particle size, liquid chromatography

In 1972, Kirkland at E. I. du Pont de Nemours patented porous silica microspheres (PSM) specifically for high-performance liquid chromatography (HPLC) applications (3). Prior to this development, silica particles used for chromatographic applications were simply adapted from some other use. In the 1970s, Kirkland showed that porous silica particles could be used for size-... 

High-pressure liquid chromatography (HPLC) is a variant of the simple column technique, based on the discovery that chromatographic separations are vastly improved if the stationary phase is made up of very small, uniformly sized spherical particles. Small particle size ensures a large surface area for better adsorption, and a uniform spherical shape allows a tight, uniform packing of particles. In practice, coated Si02 microspheres of 3.5 to 5 fxm diameter are often used. 

Reversed-phase Cig chromatography column. Keystone Scientific Betasil, 100 x 2.0-mm i.d., 5-pm particle size, 100 A, Part No. 105-701-2-CPF TSQ 7000 LC/MS/MS system with electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI) interface and gradient high-performance liquid chromatography (HPLC) unit, or equivalent Vacuum manifold for use with SPE cartridges (Varian Vac Elut 10 or equivalent)... 

Liquid chromatography/mass spectrometry (LC/MS) analysis Quantitation system Agilent Series 1100 liquid chromatograph Chromsep Omnispher 3 Cig HPLC column, 100 x 4.6-mm i.d., 3- am diameter particle size... 

The iiqwrteuice of porous layer beads in modem liquid Chromatography declined when totally porous silica mlcroparticlai3 with diameters less than 10 micrometers, and with narrow particls size ranges, became available (Figure 4.1) [4]. Indeed, vba... 

Totally porous particles of relatively large particle sizes were widely used in low pressure liquid chromatography for many years. These column packings had good sample capacity but only limited efficiency accompanied by long separation times, due to the large size and unfavorable size distribution of the particles and the presence of relatively deep pores within the particles through whick sample molecules diffused in and out of very slowly. 

In NPLC, which refers to the use of adsorption, i.e. liquid-solid chromatography (LSC), the surface of microparticulate silica (or other adsorbent) constitutes the most commonly used polar stationary phase normal bonded-phase chromatography (N-BPC) is typified by nitrile- or amino-bonded stationary phases. Silica columns with a broad range of properties are commercially available (with standard particle sizes of 3, 5 and 10 im, and pore sizes of about 6-15nm). A typical HPLC column is packed with a stationary phase of a pore size of 10 nm and contains a surface area of between 100 and 150m2 mL-1 of mobile phase volume. 

It was known from gas chromatographic theory that efficiency could be improved if the particle size of the stationary phase materials used in lc could be reduced. High performance liquid chromatography developed steadily during the late 1960s as these high efficiency materials were produced, and as improvements in instrumentation allowed the full potential of these materials to be realised. As hplc has developed, the particle size of the stationary phase used has... 

Nimura, N., Itoh, H., Kinoshita, T., Nagae, N., Nomura, M. (1991). Fast protein separation by reversed-phase high-performance liquid-chromatography on octadecylsilyl-bonded non-porous silica-gel — effect of particle-size of column packing on column efficiency. J. Chromatogr. 585(2), 207-211. 

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