Bonded phase conformation and salvation effects on the stationary phase structure in reversed-phase liquid chromatography

Schunk, T. C.; Burke, Michael

doi:10.1016/0021-9673(93)80806-j

Cited by 50 publications

(31 citation statements)

References 43 publications

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“…At lower temperatures, the C chains become more 18 rigid which will especially affect the retention behaviour of solutes that (partly) penetrate into the layer, thus giving rise to curved van't Hoff plots. This effect was already reported for other low-molarmass solutes in various reversed-phase systems [40].…”

Section: Hplc Equipment 33 Determination Of Phase Ratio and Ksec Vasupporting

confidence: 82%

Study on the retention behaviour of low-molar-mass polystyrenes and polyesters in reversed-phase liquid chromatography by evaluation of thermodynamic parameters

Philipsen¹,

Claessens

Lind³

et al. 1997

Journal of Chromatography A

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. (1997). Study on the retention behaviour of low-molar-mass polystyrenes and polyesters in reversed-phase liquid chromatography by evaluation of thermodynamic parameters. Journal of Chromatography, A, 790(1-2), 101-116. DOI: 10.1016/S0021-9673(97)00739-5 General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. AbstractPolymers can be characterized under sorption conditions, to obtain information on molar mass and chemical composition. In order to get a better understanding of their retention behaviour under such conditions, the evaluation of thermodynamic parameters obtained from van't Hoff analyses on low-molar-mass polystyrenes (PS) and polyesters (PE) in various THF-water mixtures on a C column is described in this study. Linear van't Hoff behaviour was observed in almost all 18 cases. Negative values for both DH and DS were found for both PS and PE oligomers, which increase with increasing %THF. For DS this is explained from multi-site attachment effects. For PS, the non-linear relations between DH and DS, and degree of polymerization ( p) could be properly described by the Stockmayer-Fixman equation. Although less clear, similar trends were found for PE. For PS, evidence for penetration effects of oligomer chains into the bonded chains was obtained. Martin plots for both PS and PE were shown to be non-linear in all investigated eluent compositions. The extent of non-linearity is suggested to depend on the conformation of a polymer in solution. No distinct enthalpy-entropycompensation temperature (EECT) independent of p was found for PS, thus confirming the findings of an earlier study in which no exact molar mass independence was found under critical conditions. Further evaluation of EECT for PS oligomers revealed a retention mechanism independent of the binary eluent composition. This indicates that conclusions from this study can also be used for a qualitative understanding of sorption mechanisms in the gradient elution mode. Finally, for PS it was shown that DG equals zero under critical conditions, thus confirming theoretical predictions. © 1997 Elsevier Science B. V.

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Section: Hplc Equipment 33 Determination Of Phase Ratio and Ksec Vasupporting

confidence: 82%

Study on the retention behaviour of low-molar-mass polystyrenes and polyesters in reversed-phase liquid chromatography by evaluation of thermodynamic parameters

Philipsen¹,

Claessens

Lind³

et al. 1997

Journal of Chromatography A

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“…The results show that longer chains appear to restrict the access of the bulkier molecules (larger PAHs) to the full extent of the hydrophobic surface as observed in HPLC in which the structure of the alkyl chain plays a definitive role in the control of retention and possibly selectivity. An increased chain length results in longer retention (16,18). As a consequence, and as shown in this study, the containing phase did not show to be the best phase for the extracting C 18 for any of the 16 investigated PAHs.…”

Section: N S = Kv S • V Aq • C Aq Kv S + V Aqmentioning

confidence: 51%

Coating of Solid-Phase Microextraction Fibers with Chemically Bonded Silica Particles: Selective Extraction of Polycyclic Aromatic Hydrocarbons from Drinking Water Samples

Rodrigues

Lacerda

Lanças

2002

Journal of Chromatographic Science

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In this study, solid-phase microextraction fibers coated with modified silica particles (5 pm dp) bonded to methyl (C1), hexyl (C6), octyl (C8), and polymeric octadecyl (C18) groups are prepared and evaluated. Selective extraction of polycyclic aromatic hydrocarbons (PAHs) from river water is used to demonstrate the selective behavior of the fibers as a function of the alkyl chains bonded to the silica phase. Scanning electron micrography suggests that the coating structure consists in a monolayer of particles bonded to the surface of the fiber. The behavior of the fibers upon the extraction of PAHs from water samples is compared with the use of standard polydimethylsiloxane fibers that are commercially available.

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“…The sorption of diverse mobile phase components depends on the stationary phase and mobile phase composition [38]. The hydrophobic interactions (and n-and p-electron interactions) are substituted by polar interactions in mobile phases with increased MeOH content.…”

Section: Effect Of Mobile Phase Composition On the Regression Coefficmentioning

confidence: 99%

Linear free energy relationship as a tool for characterization of three teicoplanin‐based chiral stationary phases under various mobile phase compositions

Kalíková

Lokajová

Tesařová³

2006

J of Separation Science

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Teicoplanin, teicoplanin aglycon, and methylated teicoplanin aglycon chiral stationary phases (CSPs) have been compared on the basis of the regression coefficients calculated from the linear free energy relationship (LFER) equation. The parameters have been obtained from the measurements of a set of 34 structurally diverse solutes. Influence of mobile phase composition - variation of methanol (MeOH) content - on the participation of different interactions types in the retention mechanism has been evaluated. Retention of the various interaction forces in analytes differs with both the CSP and the mobile phase composition. Hydrophobic interactions play a major role in mobile phases for high buffer contents. The more hydrophobic the CSP, the more important are they in the retention mechanism. With increase of MeOH contents in the mobile phase the major role in the interaction mechanism is shifted to more polar forces in which basicity and dipolarity/polarizability dominate. Although the LFER model does not address chiral aspects, we have attempted to explore the importance of the individual interactions in chiral discrimination of amino acids and their N-tert-butyloxycarbonyl derivatives.

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Bonded phase conformation and salvation effects on the stationary phase structure in reversed-phase liquid chromatography

Cited by 50 publications

References 43 publications

Study on the retention behaviour of low-molar-mass polystyrenes and polyesters in reversed-phase liquid chromatography by evaluation of thermodynamic parameters

Study on the retention behaviour of low-molar-mass polystyrenes and polyesters in reversed-phase liquid chromatography by evaluation of thermodynamic parameters

Coating of Solid-Phase Microextraction Fibers with Chemically Bonded Silica Particles: Selective Extraction of Polycyclic Aromatic Hydrocarbons from Drinking Water Samples

Linear free energy relationship as a tool for characterization of three teicoplanin‐based chiral stationary phases under various mobile phase compositions

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