Standardization of test conditions for high performance liquid chromatography columns

Bristow, Paul A.; Knox, John H.

doi:10.1007/bf02263001

Cited by 501 publications

(167 citation statements)

References 11 publications

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“…MAS at rates >10,000 Hz, cross-polarization (CP), high-power enhanced sensitivity, and resolution of solid-state measurements overcame these difficulties (26). Thanks to CP, proton magnetization is transferred during a distinct contact time to diluted heteronuclei, such as 29 Si or 13 C. The presence of a rigid system and attached protons leads to an effective magnetization transfer and high signal intensities. At a longer contact time, more flexible moieties of the stationary phase are polarized, and variations of contact time can be used to investi- gate the dynamic properties of adsorbents (27 ).…”

Section: Spectroscopic Methodsmentioning

confidence: 99%

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Peer Reviewed: Characterizing HPLC Stationary Phases

Krupczyńska¹,

Buszewski²

2004

Anal. Chem.

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great variety of stationary phases is available to analyze an even larger array of compounds. Stationary phases in which organic moieties (alkyl chains, aryl, amine, cholesterolic, phospholipids, phenol groups, etc.) are grafted onto a silica surface are the most popular. Sometimes the stationary phases themselves must be characterized, such as for quality control purposes. Often, interpreting chromatographic data is difficult because even columns that are "identical"-produced by the same manufacturer-exhibit different chromatographic properties. Determining the structure and properties of new stationary phases is also extremely important so that the retention mechanism, which plays a significant role in selectivity, can be described accurately. Chromatographic separation occurs because of the differences in the affinities of solute molecules for the stationary phase-retention is a process of solute transfer from a mobile phase onto/into a stationary phase (1).Column quality depends on a number of factors, the most important of which are homogeneity of both particle packing in the column bed and arrangement of the chemically bonded phase on the adsorbent surface. These factors determine the reproducibility of chromatographic data, and the large number of these factors is why there are a lot of methods for characterizing columns. Obviously, no ideal single technique can characterize all the © 2 0 0 4 A M E R

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Section: Spectroscopic Methodsmentioning

confidence: 99%

“…In some of the first work in this area, Maciel and Sindorf used 29 Si CP/MAS NMR to obtain the signals characteristic for various features of the silica structure (28). Isolated silanols were identified at ␦ = -99.8 ppm, siloxane silanols at ␦ = -109.3 ppm, and geminal silanols at ␦ = -90.6 ppm (Figure 3).…”

mentioning

confidence: 99%

Peer Reviewed: Characterizing HPLC Stationary Phases

Krupczyńska¹,

Buszewski²

2004

Anal. Chem.

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“…As can be seen, analysis time drops by more than a factor of 20 as the temperature is increased to 2008C. The importance of temperature in LC is implicit in the separation impedance (E) concept of Knox and Bristow [24]:…”

Section: Increased Analysis Speedmentioning

confidence: 99%

“…In a practical sense this means that one can use higher flow rates and still maintain resolution. In HPLC the dependence of reduced plate height (h) on reduced flow velocity (m) is usually described by the empirical Knox -Bristow [32] equation:…”

Section: Influence Of Temperature On Column Efficiencymentioning

confidence: 99%

“…2 (adapted from ref. [32]), which shows the dramatic effect of temperature on the mass transfer within the stationary phase zone (which includes the stagnant mobile phase with the particles). This improvement in efficiency is especially pronounced at higher linear velocities where the C-term is the dominant contribution to the plate height.…”

Section: Influence Of Temperature On Column Efficiencymentioning

confidence: 99%

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Practice and theory of high temperature liquid chromatography

McNeff¹,

Yan

Stoll

et al. 2007

J of Separation Science

115

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Review Practice and theory of high temperature liquid chromatographyHigh temperature liquid chromatography (HTLC) exists in a temperature region beyond ambient (ca. 408C) and below super critical temperatures. The promises of HTLC, such as increased analysis speed, enhanced separation productivity, "green" LC with pure water mobile phases coupled to universal FID detection, and fast analysis of complex samples by combination with fast 2-D techniques, have become an option for routine practice. The focus of this paper is to review the key developments that have made the application of HTLC a practical technique and draw attention to new developments in 2-D techniques that incorporate HTLC that offer an opportunity to vastly increase the usefulness of HPLC for the analysis of complex samples.

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Low aspect ratio packed capillary columns in supercritical fluid chromatography

Pyo

Wan

et al. 1996

J. Micro. Sep.

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Standardization of test conditions for high performance liquid chromatography columns

Cited by 501 publications

References 11 publications

Peer Reviewed: Characterizing HPLC Stationary Phases

Peer Reviewed: Characterizing HPLC Stationary Phases

Practice and theory of high temperature liquid chromatography

Low aspect ratio packed capillary columns in supercritical fluid chromatography

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