A Simple Apparatus for Reproducibly Packing Gas Chromatographic Columns

Villalobos, Richard

doi:10.1093/chromsci/6.7.367

Cited by 5 publications

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“…Kirkland sponds to a flow rate of 400 ml/hr and AP = 2280 psi. 6 Obtained at v = 1.18 cm/sec; 150 ml/hr; and AP = 860 psi.…”

Section: Resultsmentioning

confidence: 99%

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High-performance liquid chromatography on small particle silica gel

Majors¹

1972

Anal. Chem.

285

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Liquid chromatographic columns of 5-to 10-µ TLC grade silica gel have been packed by a high pressure, balanced density slurry technique. The columns have yielded HETP values of less than 0.1 mm at a linear velocity (v) of 1.18 cm/sec. For nitrobenzene (k' = 4.3), 15 effective plates per second were generated at 1.18 cm/sec. The HETP vs. v curve was lower than that obtained on Corasil II, a porous layer bead (PLB) adsorbent. The columns showed little loss of efficiency at high v's. The sample loading was greater than for an equal weight of PLB, but not so great as predicted by the ratio of surface areas.Porous adsorbents, such as silica and alumina, in large particle sizes (150+ µ ) have been used for many years in liquid chromatography. As the adsorbent particle diameter (dp) decreases, column efficiency should increase because of more rapid mass transfer. Snyder (1) verified experimentally for silica gel that column efficiency expressed as the HETP, (or H, Height Equivalent to a Theoretical Plate) was dependent on (dp)o s, for 20 5$ dp ^200 µ in a regularly packed column. Particles of silica smaller than 40 µ have proved difficult to pack reproducibly by dry packing techniques (/).Using small diameter kieselguhr, Huber (2) successfully packed 5-to 15-µ irregular particles by a dry-packing procedure with a controlled amount of tamping. Scott (3) preferred packing 5-to 7-µ spherical, highly cross-linked ion exchange resins in a concentrated aqueous slurry.Slurry packing has been applied to 20-µ silica gel (1), but little additional work has been reported on the successful application of the technique. This paper reports the preparation and use of columns of finely divided silica gel of a 5-to -µ particle size range which are packed by a high pressure, balanced density slurry procedure. A balanced density solvent is one that has a density equal to that of the silica so there is a minimum of particle size segregation during packing. Polystyrene-based steric exclusion chromatography packings are sometimes packed by a balanced density procedure (4). EXPERIMENTALApparatus. Columns were packed using a high pressure slurry packing apparatus shown schematically in Figure 1. A reservoir supplied liquid to a Whitey Laboratory Feed Pump Model LP-10 (Whitey Research and Tool Co., Emeryville, Calif.). This diaphragm-type pulsating pump forced the slurry from the slurry reservoir into the chromatographic column at very high flow rates and pressures. Equipped with an 8-mm plunger and 30:1 gear ratio, this pump can deliver a maximum flow rate of 1400 ml/hr and a maximum output pressure of 5000 psi.

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“…Kirkland sponds to a flow rate of 400 ml/hr and AP = 2280 psi. 6 Obtained at v = 1.18 cm/sec; 150 ml/hr; and AP = 860 psi.…”

Section: Resultsmentioning

confidence: 99%

“…Column Packing of Corasil. The Corasil was dry packed as reported previously (6). A column 50 cm X 2.1-mm i.d.…”

mentioning

confidence: 99%

High-performance liquid chromatography on small particle silica gel

Majors¹

1972

Anal. Chem.

285

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“…100-cm Packed Aluminum Columns (1.9-mm i. 6 loops. The band entering the 7th coil (i.e., the first loop in the opposite direction) will thus be broader at any point across the tube than a band which traveled the same distance in a straight column.…”

Section: Resultsmentioning

confidence: 99%

“…The influence of coiling on HETP for packed analytical columns in gas chromatography has been found negligible (5)(6)(7) because of the high diffusion coefficients of solutes in the carrier gas. The high diffusivity of the solute in the gas phase increases lateral mass transfer and thereby relaxes the concentration profile between the inside and outside bend caused by coiling.…”

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confidence: 99%

Influence of column configuration on performance in high efficiency liquid chromatography

Barth¹,

Dallmeier²,

Karger³

1972

Anal. Chem.

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Enhanced radial dispersion in open tubular column chromatography

Sumpter

Lee

1991

J Microcolumn Separations

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Abstract. Radial diffusion of solutes in the mobile phase limits the practical linear velocities that can be used to increase speed of analysis in conventional open tubular column chromatography. Several methods have been devised to enhance radial dispersion that do not depend only on molecular radial diffusion. In this review, the methods of enhancing dispersion found in the chromatographic literature are discussed. These methods include the use of deformed columns, and spinning band and static mixer columns. These techniques have been found to be of little value in analytical chromatography. Electroosmotic flow has been used to generate a plug-like flow profile in LC and generates one to two orders of magnitude lower plate height than produced at laminar flow conditions. Turbulent and secondary flow have been used to enhance radial diffusion in open tubular columns for gas, liquid, and supercritical fluid chromatography. These techniques are described from their theoretical and practical aspects. Secondary flow has also been studied by several investigators for the enhancement of radial dispersion. A circular, radial flow profile can be generated by centrifugal forces in tightly coiled columns, and after a critical velocity is achieved, columns coiled to appropriate aspect ratios yield lower plate heights than straight columns for unretained solutes as the velocity is increased. Although retained solutes yield higher plate heights in coiled rather than conventional straight columns in some cases due to the resistance to mass transfer at the interphase region, higher speeds of analysis are obtained. Secondary flow chromatography has been successfully applied in gas and supercritical fluid chromatography for the rapid separation of alkanes having low retention. Nevertheless, applications using secondary flow in chromatographic separations are limited.

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A Simple Apparatus for Reproducibly Packing Gas Chromatographic Columns

Cited by 5 publications

References 0 publications

High-performance liquid chromatography on small particle silica gel

High-performance liquid chromatography on small particle silica gel

Influence of column configuration on performance in high efficiency liquid chromatography

Enhanced radial dispersion in open tubular column chromatography

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