Influence of column configuration on performance in high efficiency liquid chromatography

Barth, Howard G.; Dallmeier, Erwin; Karger, Barry L.

doi:10.1021/ac60319a008

Cited by 13 publications

(5 citation statements)

References 17 publications

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“…Figure 1 presents H vs. velocity plots for Corasil I alone and 0.05% TNF impregnated on Corasil I with dry heptane as mobile phase. For unretained components efficiencies comparable to those published in the literature for Corasil I (15,16) are attained. As k' for solutes increases, the efficiency at any given velocity decreases.…”

Section: Resultssupporting

confidence: 75%

“…The tubing connections were filled with packing material. Since coiling with a small radius of curvature results in loss in efficiency (15) k^-capacity ratio on TNF impregnated Corasil I (b) Tailing was bad for this compound on both the Corasil I and 0.05 % TNF columns the column was made into a U shape with straight lengths of 1.5 meters each. This column was not thermostated.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Separation of polyaromatic hydrocarbons by liquid-solid chromatography using 2,4,7-trinitrofluorenone impregnated Corasil I columns

Karger¹,

Martin²,

Lohéac³

et al. 1973

Anal. Chem.

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Section: Resultssupporting

confidence: 75%

Section: Discussionmentioning

confidence: 99%

Separation of polyaromatic hydrocarbons by liquid-solid chromatography using 2,4,7-trinitrofluorenone impregnated Corasil I columns

Karger¹,

Martin²,

Lohéac³

et al. 1973

Anal. Chem.

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“…The effect of column shape in LC was experimentally explored by Bart,h et al (11). Significant H increases were observed with columns of conventional diameters, but no particular changes were observed for a 0.76-mm i.d.…”

Section: Literature Citedmentioning

confidence: 99%

“…If hydrodynamic factors are involved in the zone broadening phenomena, it is of some interest to investigate whether the column coil radius can influence the plate height as well. This situation received some attention previously (9)(10)(11) with different column types. The results obtained with the columns of identical inner diameter and particle size, but different column coil radii, are shown in Figure 7.…”

Section: Dpmentioning

confidence: 99%

Packed microcapillary columns in high performance liquid chromatography

Tsuda¹,

Novotný²

1978

Anal. Chem.

183

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New high-pressure LC (packed microcapillary) columns are described which consist of small adsorbent particles drawn Inside glass capillaries of 50-200 pm internal diameters. A typical ratio of the column inner diameter to particle size is 2, and a significant plate-height reduction is achieved with decreasing particle size. With typical flow rates of several pL/min through such columns, modlfied injection and detection techniques are necessary. The columns of different inner diameters and particle sizes were evaluated through the reduced plate height vs. velocity plots. The effect of column coiling diameter on chromatographlc performance was also studied. Whereas sample capacity of packed microcapillary columns is low, typical column efficiencies are significantly higher than those obtained with the hitherto available LC c o I u m n s .T h e basic types of columns available in analytical gas chromatography (GC) are conventional packed columns, open tubular (capillary) columns, micropacked columns (with typical internal diameters around 1 mm), and packed capillary columns. These columns differ widely in terms of separation efficiency and sample capacity. Selection of a column type in liquid chromatography (LC) has been more restricted because of viscosities and solute diffusivities in the liquid phase which are orders of magnitude different from the values in the gas phase.T h e most efficient columns presently used in LC are those packed with totally porous small particles (with particle size down to several micrometers). T h e other column types, as known in GC, have not been sufficiently explored. This is primarily due t o t h e fact that the mass transfer is a diffusion-controlled process. Thus, capillary LC is unlikely to give desired efficiencies under t h e conditions of laminar flow.Packed capillary columns studied extensively in GC byHalasz and Heine ( I ) and Landault and Guiochon (2) have rather unique characteristics. Their technology is different from other column types in that t h e adsorptive material is drawn inside the glass capillaries, in a way that is somewhat similar to the very common method for preparation of glass capillary helices (3). However, according to Halasz and Heine ( I ) , t h e most important feature of such columns is the ratio of particle size to the internal column diameter. Whereas packed capillaries possess usual values of this ratio between 0.2 and 0.5, t h e conventional packed columns are typically well below 0.1. Thus, packed capillaries have certain geometrical characteristics of their own which are reflected in their analytical performance. Considering a rather loose packing of these columns used in GC, their efficiencies are quite high. Halasz and Heine ( 1 ) attribute this to the mobile-phase mixing effect that aids the radial diffusion and stress t h e importance of high column permeability.When comparing the theoretical separating power of GC and LC with t h e actual situation, Giddings ( 4 , 5 ) and Golay (6) note that, unlike in GC where a reasonable approach has...

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“…Several researchers have contributed to the modern theoretical development of secondary flow, but the most comprehensive studies pertaining to its chromatographic application have been done by Tijssen and coworkers (41,58,(72)(73)(74)(75). Tijssen (81) proposed that the total radial dispersion, DR, could be described as the sum of its components where DM,R is the molecular radial diffusion in the mobile phase, and D, is the contribution to dispersion of the molecules due to secondary flow.…”

Section: Plate Heights Under Secondary Flow Conditionsmentioning

confidence: 99%

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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Influence of column configuration on performance in high efficiency liquid chromatography

Cited by 13 publications

References 17 publications

Separation of polyaromatic hydrocarbons by liquid-solid chromatography using 2,4,7-trinitrofluorenone impregnated Corasil I columns

Separation of polyaromatic hydrocarbons by liquid-solid chromatography using 2,4,7-trinitrofluorenone impregnated Corasil I columns

Packed microcapillary columns in high performance liquid chromatography

Enhanced radial dispersion in open tubular column chromatography

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