Structure-Function Relationships in High-Density Octadecylsilane Stationary Phases by Raman Spectroscopy. 2. Effect of Common Mobile-Phase Solvents
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- 作者：Michael W. Ducey ; Jr. ; Christopher J. Orendorff ; Jeanne E. Pemberton ; and Lane C. Sander
- 刊名：Analytical Chemistry
- 出版年：2002
- 出版时间：November 1, 2002
- 年：2002
- 卷：74
- 期：21
- 页码：5585 - 5592
- 全文大小：162K
- 年卷期：v.74,no.21(November 1, 2002)
- ISSN：1520-6882
文摘
Raman spectroscopy is used to examine the effects ofsolvent, temperature, and surface grafting method (surface or solution polymerized) on alkyl chain rotational andconformational order in a series of high-density octadecylsilane stationary phases ranging in surface coveragefrom 3.09 to 6.45 
mol/m2. Rotational and conformational order is assessed using the intensity ratio of theantisymmetric to symmetric 
(CH2) modes as well as thefrequency at which these Raman bands are observed.Solvents studied include perdeuterated hexane, toluene,chloroform, tetrahydrofuran, benzene, methanol, acetone,acetonitrile, and water. Stationary-phase order was investigated at temperatures between 258 and 323 K. Alkylchain rotational and conformational order, and hence,solvation of the stationary phase, is dependent on solventparameters (polarity, size, etc.), temperature, and stationary-phase properties (polymerization method and surfacecoverage). Information on stationary-phase conformational order allows solvent-stationary-phase interactionsto be described in terms of a combination of adsorptionand partitioning models for reversed-phase liquid chromatography. Finally, a distinct interplay between solvent-and temperature-induced ordering of these stationaryphases is documented that is also a function of solventand stationary-phase properties.
mol/m2. Rotational and conformational order is assessed using the intensity ratio of theantisymmetric to symmetric (CH2) modes as well as thefrequency at which these Raman bands are observed.Solvents studied include perdeuterated hexane, toluene,chloroform, tetrahydrofuran, benzene, methanol, acetone,acetonitrile, and water. Stationary-phase order was investigated at temperatures between 258 and 323 K. Alkylchain rotational and conformational order, and hence,solvation of the stationary phase, is dependent on solventparameters (polarity, size, etc.), temperature, and stationary-phase properties (polymerization method and surfacecoverage). Information on stationary-phase conformational order allows solvent-stationary-phase interactionsto be described in terms of a combination of adsorptionand partitioning models for reversed-phase liquid chromatography. Finally, a distinct interplay between solvent-and temperature-induced ordering of these stationaryphases is documented that is also a function of solventand stationary-phase properties.