TY - JOUR
T1 - Structure-function relationships in high-density octadecylsilane stationary phases by Raman spectroscopy. 2. Effect of common mobile-phase solvents
AU - Ducey, Michael W.
AU - Orendorff, Christopher J.
AU - Pemberton, Jeanne E.
AU - Sander, Lane C.
PY - 2002/11/1
Y1 - 2002/11/1
N2 - Raman spectroscopy is used to examine the effects of solvent, temperature, and surface grafting method (surface or solution polymerized) on alkyl chain rotational and conformational order in a series of high-density octadecylsilane stationary phases ranging in surface coverage from 3.09 to 6.45 μmol/m2. Rotational and conformational order is assessed using the intensity ratio of the antisymmetric to symmetric v(CH2) modes as well as the frequency 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. Alkyl chain rotational and conformational order, and hence, solvation of the stationary phase, is dependent on solvent parameters (polarity, size, etc.), temperature, and stationary-phase properties (polymerization method and surface coverage). Information on stationary-phase conformational order allows solvent-stationary-phase interactions to be described in terms of a combination of adsorption and partitioning models for reversed-phase liquid chromatography. Finally, a distinct interplay between solvent-and temperature-induced ordering of these stationary phases is documented that is also a function of solvent and stationary-phase properties.
AB - Raman spectroscopy is used to examine the effects of solvent, temperature, and surface grafting method (surface or solution polymerized) on alkyl chain rotational and conformational order in a series of high-density octadecylsilane stationary phases ranging in surface coverage from 3.09 to 6.45 μmol/m2. Rotational and conformational order is assessed using the intensity ratio of the antisymmetric to symmetric v(CH2) modes as well as the frequency 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. Alkyl chain rotational and conformational order, and hence, solvation of the stationary phase, is dependent on solvent parameters (polarity, size, etc.), temperature, and stationary-phase properties (polymerization method and surface coverage). Information on stationary-phase conformational order allows solvent-stationary-phase interactions to be described in terms of a combination of adsorption and partitioning models for reversed-phase liquid chromatography. Finally, a distinct interplay between solvent-and temperature-induced ordering of these stationary phases is documented that is also a function of solvent and stationary-phase properties.
UR - http://www.scopus.com/inward/record.url?scp=0036828737&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0036828737&partnerID=8YFLogxK
U2 - 10.1021/ac0203490
DO - 10.1021/ac0203490
M3 - Article
C2 - 12433092
AN - SCOPUS:0036828737
SN - 0003-2700
VL - 74
SP - 5585
EP - 5592
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 21
ER -