Application of the solvation parameter model to poly(methylcyanopropylsiloxane) stationary phases

Tello, Ana María; Lebrón-Aguilar, Rosa; Quintanilla-López, Jesús Eduardo; Pérez-Parajón, J.M.; Santiuste, J. M.

doi:10.1016/j.chroma.2006.04.060

Cited by 15 publications

(6 citation statements)

References 43 publications

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“…Each of the configurations is called a solvation structure. Nowadays, people gradually perceive that the solvation structures, especially detailed solvation structures, are very important and are found in many disciplines, such as life science, − pharmacy, − lavation, − etc. For example, the conformational stability of human polyclonal IgG in solution decreases with a decreasing pH; to know the reason, one must study the detailed solvation structure.…”

Section: Introductionmentioning

confidence: 99%

Detailed Structures and Mechanism of Polymer Solvation

Yang

2006

J. Phys. Chem. B

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In the present study, we simulated a model system, PE in biphenyl, to gain the insight into the detailed solvation structures and the molecular mechanism of polymer chain solvation. Using atomistic molecular dynamics (MD) simulation, it was found that when the biphenyl is far from PE chain or in the bulk, the dihedral angle of the two rings in the solvent molecule are approximately 32 degrees. But, the dihedral angel is about 27 degrees when the biphenyls are very close to the PE chain. In the first solvation shell, the orientation angle of the biphenyl long axis to the chain segment backbone was found to be enhanced around two values: approximately 0 and approximately 60 degrees. The detailed solvation structures found here include all dyad conformations (TT, TG, TG', GT, GG, GG', G'T, G'G, and G'G') and vary as a function of the distance between PE chain and biphenyls in the first solvation shell. The closer the the solvent molecule to the PE segment, the higher the TT conformation fraction response is. The other dyad conformations such as TG, GG', etc. undergo different decreases, respectively. This study shows that the solvation even in the Theta condition makes the overall size expansion or the chain stretched. Such a cooperative change was examined here and found not due to generating or losing a conformational state but due to a change in conformational distribution. This change occurs in the middle location of the chain instead of the chain end locations.

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Section: Introductionmentioning

confidence: 99%

Detailed Structures and Mechanism of Polymer Solvation

Yang

2006

J. Phys. Chem. B

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“…For the OV-25 stationary phase, which is not a crystalline liquid, the above mentioned differences between heating and cooling were not observed. According to several studies on other amorphous liquid stationary phases [19,20], intermolecular forces expressed by the coefficients s, a, b and l were found to be linearly decreasing with increasing temperatures.…”

Section: Resultsmentioning

confidence: 97%

“…These properties were investigated in the present paper through Abraham's equation (eq.1), because the temperature variations of coefficients in eq.1 correspond to changes in the contributions to the retention time of the abovementioned interactions (namely polarity, H-bond donor/acceptor and dispersion interactions). Such studies have been communicated in the case of several amorphous polymers [19,20]. The temperature range was chosen so as to include the phase transition for each of the studied compounds, in order to monitor the changes in the properties of the liquid-crystal stationary phase.…”

Section: Introductionmentioning

confidence: 99%

Study of Intermolecular Interactions Involved in Capillary GLC with Liquid Crystal Compounds as Stationary Phases

Spafiu¹

2012

TOCPJ

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Abraham's equation was employed in order to investigate nonspecific intermolecular interactions involving liquid crystals. Several aromatic azo derivatives, proved to have liquid crystal behavior, were used as stationary phases in capillary gas chromatography. The polarizability, polarity, hydrophobicity and hydrogen-bond donor or acceptor characters were estimated using the Abraham solvation model. Calculations were based on the isothermal retention times for 25 compounds, in the temperature range between 70˚ and 170˚C, both in the heating and the cooling mode. The descriptors R, , , , and logL 16 (Abraham parameters) were converted into orthogonal descriptors following Randi 's procedure. The above-mentioned properties involve the r, s, a, b and l coefficients, respectively, which were determined by means of multilinear regression applied to the considered set. Following the orthogonalization procedure, the polarizability term (rR*) was found to be statistically insignificant in the case of the studied compounds. Plots of these coefficients vs temperature are discussed, in order to allow estimations regarding the retention mechanism and contributions of polar and Van der Waals interactions. The variation of properties (e.g. polarity, hydrogen-bond donor and hydrogen-bond acceptor character) with temperature was assigned to the changes in the molecular geometry of the compound used as stationary phase.

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“…34 Concurrent Retention Mechanism. According to Conder et al, retention which combines partition and interfacial adsorption can be expressed as follows: 35 8) where V N is the net retention volume which is the same as in eq 1, V L is the volume of SP, and A GL and A LS are the gas−liquid and liquid−solid interfacial areas, respectively. The partition coefficients K L , K GL , and K GLS correspond to dissolution in the SP and to adsorption at the gas−liquid and liquid−solid interfaces, respectively.…”

Section: ■ Theory and Calculationsmentioning

confidence: 99%

Accurate Measurements of Infinite Dilution Activity Coefficients Using Gas Chromatography with Static-Wall-Coated Open-Tubular Columns

Luo

et al. 2012

Anal. Chem.

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Wall-coated open-tubular (WCOT) columns provide higher column efficiency and lower solute interfacial adsorption effect than packed columns. However, previous efforts used to measure the infinite dilution activity coefficient (γ(∞)) via a chromatographic technique have used packed columns, because the low carrier gas flow rate (U) and the small stationary phase amount (n(2)) in WCOT columns raise large errors. By rationally revising the γ(∞)-calculation equation for static-wall-coated open-tubular column, we observed that U and n(2) are not necessarily needed and the resulting error could be reduced, and WCOT column gas chromatography subsequently became a superior method for the accurate γ(∞) determination. In this study, we validate our revised γ(∞)-calculation equation by measuring γ(∞) in an ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate system, in which 55 organic compounds covering a wide range of functional groups were used as probe solutes and their γ(∞) values in the ionic liquid were determined at 40.0, 50.0, and 60.0 °C. Experimental error analysis shows that our revised equation remarkably reduces the error compared to the common γ(∞)-calculation equation. Our data is consistent with previously reported values obtained via other techniques, which further proves the credibility of our revised equation. The accurately determined γ(∞) values can be directly used to calculate the partial molar excess enthalpy, selectivity, and capacity, which will benefit for the rapid screening of solvents (especially ionic liquids) in separation approaches.

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Application of the solvation parameter model to poly(methylcyanopropylsiloxane) stationary phases

Cited by 15 publications

References 43 publications

Detailed Structures and Mechanism of Polymer Solvation

Detailed Structures and Mechanism of Polymer Solvation

Study of Intermolecular Interactions Involved in Capillary GLC with Liquid Crystal Compounds as Stationary Phases

Accurate Measurements of Infinite Dilution Activity Coefficients Using Gas Chromatography with Static-Wall-Coated Open-Tubular Columns

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