Comparison of Thermodynamic Retention Behaviors on Various C18 Columns Different in Their Hydrophobicity

Yamamoto, Fumiko M.; Rokushika, Souji; Hatano, Hiroyuki

doi:10.1093/chromsci/27.12.704

Cited by 34 publications

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“…The compensation temperatures which were deter-3076248C (95% confidence intervals) for oligomers mined from linear regression analysis of the entire 3-15 and 147668C for oligomers [16][17][18][19][20][21][22][23][24][25][26]. The fact curves for both polymers are 175688C for PS and that both values differ significantly, again indicate a 1206128C for PE.…”

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

confidence: 99%

“…r 0 0 d tography (RPLC) is to investigate the temperature dependence of isocratic retention [15][16][17][18][19][20][21][22][23][24][25][26][27]. From the in which K is the chromatographic equilibrium In order to get a better understanding of their DS are the Gibbs free energy, standard enthalpy and retention behaviour, in this study the determination standard entropy of transfer of a solute from the and evaluation of thermodynamic parameters for mobile to the stationary phase.…”

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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 Vamentioning

confidence: 99%

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confidence: 99%

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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“…These data are not always provided by the manufacturers and are often difficult to obtain. Sander and Field (39) proposed a f value of 0.384, and Yamamoto et al (44) reported ф values ranging between 0.351 and 0.819 for different C18 columns.…”

Section: Resultsmentioning

confidence: 99%

Effect of Temperature on Retention of Cyclic ( -Amino Acid Enantiomers on a Chiral Crown Ether Stationary Phase

Péter¹,

Török²,

Fülöp

1998

Journal of Chromatographic Science

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The isocratic retention of cyclic β-amino acids is studied on a chiral crown ether column (Crownpak CR [+]) at different temperatures. The natural logarithm of the retention factor (In k) depends linearly on the inverse of temperature (1/7). van't Hoff plots afford thermodynamic parameters, such as the apparent change of enthalpy (AH 0 ) and the apparent change of entropy (AS 0 ) for the transfer of analyte from the mobile phase to the stationary phase. The information obtained from the thermodynamic study is discussed, and the qualitative relationships between the structure and the thermodynamic data are evaluated.

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“…The thermodynamic relationship between the capacity factor (k') and temperature (T) was used to obtain solute transfer enthalpies and entropies and is as follows [1][2][3][4][5][6][7][8][9][10] :…”

Section: Methodsmentioning

confidence: 99%

“…The chromatographic enthalpies and entropies for the solute transfer from the mobile to the stationary phase can be obtained by measuring retention data over a wide range of temperature [1][2][3][4][5][6][7][8][9][10][11][12] and the specific solute functional group-mobile phase interaction can be derived from such thermodynamic data. [13][14][15][16][17] In our previous studies, we measured the specific hydroxyl group-solvent and carbonyl group-solvent interaction enthalpies and entropies of phenol and acetophenone in aqueous methanol mixtures using the squalane-impregnated C 18 stationary phase, 13 the specific functional group-solvent interaction enthalpies and entropies of phenol, benzylalcohol, phenenthylalcohol, acetophenone, and benzylacetone in aqueous acetonitrile mixtures using the squalane-impregnated C 18 stationary phase, 16 and the specific functional group-solvent interaction enthalpies and entropies of 4 positional isomers of phenylbutanol, 5-phenyl-1-pentanol, 3 positional isomers of alkylarylketone derived from butylbenzene, and 1-phenyl-2-hexanone in aqueous methanol mixtures using the Alltima C 18 stationary phase.…”

Section: Introductionmentioning

confidence: 99%

The Hydroxyl Group-Solvent and Carbonyl Group-Solvent Specific Interactions for Some Selected Solutes Including Positional Isomers in Acetonitrile/Water Mixed Solvents Monitored by HPLC

2002

Bulletin of the Korean Chemical Society

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We have evaluated the specific hydroxyl group-solvent and carbonyl group-solvent interactions by using an Alltima C18 stationary phase and by measuring the retention data of carefully selected solutes in 60/40, 70/30, and 80/20(v/v%) acetonitrile/water eluents at 25, 30, 35, 40, 45, and 50 o C. The selected solutes are phenol, acetophenone, alkylbenznes(benzene to hexylbenznene), 4 positional isomers of phenylbutanol, 5-phenyl-1-pentanol, 3 positional isomers of alkylarylketone derived from butylbenzene, and 1-phenyl-2-hexanone. The magnitudes of hydroxyl group-acetonitrile/water specific interaction enthalpies are larger than those of carbonyl group-acetonitrile/water specific interaction enthalpies in general while the magnitudes of carbonyl group-methanol/water specific interaction enthalpies are larger than those of hydroxyl group-methanol/water specific interactions. We observed clear discrepancies in functional group-solvent specific interaction among positional isomers. The variation trends of solute transfer enthalpies and entropies with mobile phase composition in the acetonitrile/water system are much different from those in the methanol/water system. The well-known pocket formation of acetonitrile in aqueous acetonitrile mixtures has proven to be useful to explain such phenomena.

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Comparison of Thermodynamic Retention Behaviors on Various C18 Columns Different in Their Hydrophobicity

Cited by 34 publications

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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

Effect of Temperature on Retention of Cyclic ( -Amino Acid Enantiomers on a Chiral Crown Ether Stationary Phase

The Hydroxyl Group-Solvent and Carbonyl Group-Solvent Specific Interactions for Some Selected Solutes Including Positional Isomers in Acetonitrile/Water Mixed Solvents Monitored by HPLC

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