Retention mechanisms in reversed-phase liquid chromatography.  Stationary-phase bonding density and partitioning

Sentell, Karen B.; Dorsey, John G.

doi:10.1021/ac00184a003

Cited by 164 publications

(98 citation statements)

References 42 publications

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“…The use of polar stationary phases resulted in significantly poorer regression coefficients than the other phases. This is likely due to significant degrees of adsorptive interactions, in addition to the partitioning of solute between the mobile and stationary phases [22][23][24]. In our experience, mixed retention mechanisms result in poor LSER regression fits.…”

Section: Effect Of Additives With Various Stationary Phasesmentioning

confidence: 69%

Study of the Effect of Mobile Phase Additives on Retention in Reversed Phase HPLC Using Linear Solvation Energy Relationships

Blackwell¹,

Carr

1998

J. High Resol. Chromatogr.

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Linear solvation energy relationships (LSERs) were used to delineate which specific intermolecular interactions are responsible for changes in retention for a variety of well characterized analytes when acidic and basic additives were used in reversed phase HPLC. The effects of trifluoroacetic acid, triethylamine and a combination of trifluoroacetic acid and triethylamine on the LSERs were compared to those observed in the absence of additives. These effects were examined using four different mobile phase modifiers and five different stationary phases. Trifluoroacetic acid alone and in combination with triethylamine produced LSER regression coefficients nearly identical to those obtained with no additive present in the mobile phase. Triethylamine alone produced different LSER regression coefficients from the other systems unless the mobile phase contained trifluoroethanol as the mobile phase modifier, or the stationary phase consisted of a polymeric support.

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Section: Effect Of Additives With Various Stationary Phasesmentioning

confidence: 69%

Study of the Effect of Mobile Phase Additives on Retention in Reversed Phase HPLC Using Linear Solvation Energy Relationships

Blackwell¹,

Carr

1998

J. High Resol. Chromatogr.

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“…According to Sander et al, the molecular-shape selectivity can be explained by the immobilization density of an octadecyl group on silica, and thus distinct enhanced selectivity can be realized by high-density ODS (more than 25 wt%). 33,34 However, our silica-supported ODAn used in this study has only 16.4 -18.5 wt% in the organic phase, and thus the content of an octadecyl group is even smaller (15 wt%), but the α value is much higher than that of conventional ODS. This is not only because ODAn has carbonyl groups as a π-electron source for an electrostatic interaction but also because it can form ordered structures at temperatures below Tc to promote multiple π-π interactions.…”

Section: Discussionmentioning

confidence: 89%

Conformational Effect of Silica-supported Poly(octadecyl acrylate) on Molecular-Shape Selectivity of Polycyclic Aromatic Hydrocarbons in RP-HPLC

et al. 2004

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Hydrophobized silicas, such as octadecylated silicas, are very useful as packing materials for reversed-phase high performance liquid chromatography, RP-HPLC. A simple modification of the mobile phase has expanded their applicability in analytical chemistry and separation technology. Similarly, a chemical modification of an organic phase on silica has provided versatility in the separation mode even in RP-HPLC. For these reasons, unique organic stationary phases have been created during the past decade. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Fullerene C60 bonded silica 3,4 showed higher selectivity for calixarene isomers, fullerenes C60 and C70, and polycyclic aromatic hydrocarbons (PAHs). The stationary phases containing heavy atoms, such as sulfur, chlorine and bromine resulted in longer retentions of fullerenes. 2Various porphyrin-silica stationary phases, [6][7][8] alkyl diphenyl-silicas 1 and (2,4,6-tri-tertbutylphenoxy)dimethyl-silicas 5 exhibited extraordinary shape selectivity in the separation of PAHs and fullerenes. We have reported that polymer-grafted silica exhibited selective separation in HPLC. Polymers with trimethoxysilyl terminal groups were synthesized using the telomerization method and chemically-grafted on silica particles. A number of synthetic polymers, such as poly(styrene), 10 poly(acrylonitrile), 11 poly(methylacrylate), 9,12 poly(vinylpyridine) 16 and poly(Lalanine), 14,15 were used to develop the polymer-silica hybrid materials as a stationary phase of HPLC. On the other hand, we have proposed that self-assembled systems, such as lipid aggregates, can provide a highly-ordered microenvironment leading to unique host-guest chemistry exceeding the functions of the original lipid. 17 Based on these points, we have focused on the ordered structures of poly(octadecyl acrylate), ODAn and the ODAn-grafted silica for applying to RP-HPLC.18 Through these studies, we recognize that the weak subsidiary effects due to the carbonyl groups in the polymer work as main driving force for molecular-shape selectivity toward π-electron-containing compounds and the selectivity is specifically enhanced by ordering of the long-chain alkyl moieties. [19][20][21][22] The present study is aimed at controlling the ordered state of ODAn (Fig. 1) by the polymerization condition, and evaluating its effect on the selectivity, with HPLC toward the structural isomers of terphenyls and four-ring polyaromatic hydrocarbons and with differential scanning calorimetry and NMR spectroscopy. Chemistry & Engineering, Kyushu University, Japan Poly(octadecyl acrylate) with a terminal reactive group was synthesized by radical telomerization in various solvents. The polymers were grafted onto porous silica for use in RP-HPLC, and the molecular recognition ability was investigated along with the selectivity for the structural isomers of polycyclic aromatic hydrocarbons. The mechanism of selectivity was also investigated with differential scanning calorimetry and NMR spectroscopic observations. Experimental

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“…On the other hand, the two calculated surface coverages (2.89 for Pro C18 and 2.69 for Pro C18 RS) are close and below the value reported by Sentell and Dorsey (3.1 mmol/m 2 ) for C18-bonded chain. Consequently, the decrease in the partition coefficient due to a high surface coverage cannot explain the retention behaviour observed on the two YMC [20].…”

Section: Properties Of High-loaded Phasesmentioning

confidence: 94%

“…The calculated surface coverage is equal to 3.52 for ODS2 and 1.95 for ODS3. In this case, the change in the partition coefficient due to an entropic phenomenon could be evoked [20], due to the great difference between the two Prodigy phases, to explain why the retention on ODS2 seems lower than it should be.…”

Section: Properties Of New Phases Derived From An Older Versionmentioning

confidence: 97%

Extension of the C18 stationary phase knowledge by using the carotenoid test

Lesellier

2010

J of Separation Science

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The carotenoid test for octadecylsiloxane-bonded stationary phases used in RPLC was developed some years ago. Additional experiments have now been performed with varied stationary phases. The effect of the bonding density and of the pore diameter on steric selectivity, polar surface activity and hydrophobicity was determined by using YMC series (J'Sphere and Pack ODSA). The test was also extended to estimate the phase evolution of several classical or hybrid silicas. The high loading phases were also studied, as well as the fused core silicas. The effect of the particle size reduction on the three previous phase properties was investigated in the goal to determine in which way this parameter could also modify the chemical properties of the phases.

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Retention mechanisms in reversed-phase liquid chromatography. Stationary-phase bonding density and partitioning

Cited by 164 publications

References 42 publications

Study of the Effect of Mobile Phase Additives on Retention in Reversed Phase HPLC Using Linear Solvation Energy Relationships

Study of the Effect of Mobile Phase Additives on Retention in Reversed Phase HPLC Using Linear Solvation Energy Relationships

Conformational Effect of Silica-supported Poly(octadecyl acrylate) on Molecular-Shape Selectivity of Polycyclic Aromatic Hydrocarbons in RP-HPLC

Extension of the C18 stationary phase knowledge by using the carotenoid test

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