Characterization of the surface composition of alkyl bonded phases under reversed-phase liquid chromatographic conditions using homologues of alkanoate and perfluoroalkanoate esters as solute probes

Gilpin, R. K.; Jaroniec, Mietek; Lin, S.

doi:10.1021/ac00218a009

Cited by 34 publications

(21 citation statements)

References 44 publications

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“…Similarly, although the dependence of retention and selectivity on the chain length of alkyl bonded phases has been studied extensively (see refs 9-11 and the citations in ref 9), again the influence of intercalated solvents has been neglected. Recently, more quantitative treatments have been suggested (12)(13)(14) which consider both the competitive interactions that arise between the solute and solvents for a chemically modified solid as well as the solute-solvent and solvent-solvent interactions that occur in both the mobile and stationary phases (15)(16)(17)(18)(19)(20). In doing this an accurate description of the stationary phase's composition is needed since it may be significantly different than that of the eluent (12, 13, [21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Studies of the surface composition of phenyl and cyanopropyl bonded phases under reversed-phase liquid chromatographic conditions using alkanoate and perfluoroalkanoate esters

Gilpin¹,

Jaroniec²,

Lin³

1991

Anal. Chem.

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Two polar bonded phases, phenyl-silica and cyanopropylsllica, have been studied under reversed-phase conditions using homologues of alkanoate and perfluoroalkanoate esters as test solutes. For comparative purposes a similarly prepared n -butyl phase also has been studied under equivalent conditions. Retention measurements have been carried out as a function of mobile-phase composition for water-methanol and water-acetonitrile and Incremental methylene (-CH2-) and perfluoromethylene (~CF2~) selectlvltles calculated. These latter data have been used to estimate the thermodynamic constant K^, which describes the sorption equilibrium of solvents between mobile and stationary phases assuming Ideality of these phases. For water-methanol, differences In composition between the mobile and surface phases due to preferential Intercalation are small. However, the data Indicate a significant sorption excess of acetonitrile by the bonded phases. This preferential sorption of acetonitrile Is greatest for alkyl phases and decreases with increasing polarity of the bonded phase (l.e., cyano-silica < phenyl-silica < alkyl-silica).

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Section: Introductionmentioning

confidence: 99%

Studies of the surface composition of phenyl and cyanopropyl bonded phases under reversed-phase liquid chromatographic conditions using alkanoate and perfluoroalkanoate esters

Gilpin¹,

Jaroniec²,

Lin³

1991

Anal. Chem.

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“…Conversely, acetonitrile exhibits preferential sorption onto the alkyl bonded phase in comparison to water for water-acetonitrile-alkyl bonded phase systems. [25] This enrichment of organic modifier in the stationary phase is manifested as an adsorbed phase on top of the bonded layer. [26 -28] The methanol layer is determined to be monomolecular while the THF and acetonitrile layers have a thickness consistent with multiple layers.…”

Section: A Retention Model For Polar Selectivity In Reversed Phase Chmentioning

confidence: 99%

A Retention Model for Polar Selectivity in Reversed Phase Chromatography as a Function of Mobile Phase Organic Modifier Type

Zhuang

Thompson

O'Brien

2005

Journal of Liquid Chromatography & Related Technologies

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Elucidation of solute retention as a function of the mobile phase modifier type under reversed phase conditions was investigated. The retention of steroid analogues were determined using methanol, acetonitrile, and tetrahydrofuran. Quantitative structure versus retention relationships (QSRRs) were then determined through the use of a de novo mathematical model. The results indicate that interactions between the solute and organic modifier that is extracted into the stationary phase play a significant role in the observed selectivity differences. Thermodynamic studies were conducted to further confirm the finding of the QSRRs determinations.

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“…A mixture of alkane and methanol was a comparable model with the stationary phase in the ODS/methanol system [25]. Molecular dynamics simulation showed that the Gibbs free energy of a solute (methane) had a minimum at the ODS/(methanol-water) interface, where the solute was surrounded by the alkyl moiety on ODS and methanol [21].…”

Section: Originalmentioning

confidence: 99%

“…Most researchers, however, have not taken this information into consideration when discussing the mechanism of retention of RPLC. There have, furthermore, so far been few studies of the quantitative influence of penetrating components on solute retention [21,22].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Gibbs free energies of tris(β-diketonato) chromium (III),-cobalt(III), and bis(β-diketonato)palladium(II) in reversed-phase liquid chromatography on octadecyl-bonded silica gel with acetonitrile-water mobile phases

2000

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Key WordsColumn liquid chromatography Gibbs free energy Octadecyl-bonded silica gel Liquid-liquid partition coefficient SummaryTo clarify the mechanism of retention of several fldiketonates of chromium(III), cobalt(III), and palladium(II) in reversed-phase liquid chromatography (RPLC), their capacity factors (k) were measured on an octadecyl-bonded silica gel (ODS) stationary phase with acetonitrile-water binary mobile phases. The values obtained were compared with the liquid-liquid partition coefficients (P) of the metal fl-diketonates in the dodecane/(acetonitrile-water mixture) system. This comparison showed that with regard to the distribution of the metal fl-diketonates the nature of the stationary phase was similar to, but not identical with, that of dodecane. When the Gibbs free energies of the metal fldiketonates in the stationary phase were calculated, the values showed that the cavity-formation free energy for each metal fl-diketonate in the stationary phase was close to that in dodecane, and the interaction free energy was almost equal to the sum of the energies of interaction with the alkyl moiety and with acetonitrile. This implies that acetonitrile molecules from the mobile phase penetrate the alkyl moiety of ODS.

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Characterization of the surface composition of alkyl bonded phases under reversed-phase liquid chromatographic conditions using homologues of alkanoate and perfluoroalkanoate esters as solute probes

Cited by 34 publications

References 44 publications

Studies of the surface composition of phenyl and cyanopropyl bonded phases under reversed-phase liquid chromatographic conditions using alkanoate and perfluoroalkanoate esters

Studies of the surface composition of phenyl and cyanopropyl bonded phases under reversed-phase liquid chromatographic conditions using alkanoate and perfluoroalkanoate esters

A Retention Model for Polar Selectivity in Reversed Phase Chromatography as a Function of Mobile Phase Organic Modifier Type

Evaluation of the Gibbs free energies of tris(β-diketonato) chromium (III),-cobalt(III), and bis(β-diketonato)palladium(II) in reversed-phase liquid chromatography on octadecyl-bonded silica gel with acetonitrile-water mobile phases

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