Poole C F, Li Q, Kiridena W, Koziol W W
Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.
J Chromatogr A. 2000 Nov 17;898(2):211-26. doi: 10.1016/s0021-9673(00)00829-3.
The solvation parameter model is used to study differences in selectivity for poly(ethylene glycol) stationary phases for packed column (Carbowax 20M) and fused-silica, open-tubular column (HP-20M, AT-Wax, HP-INNOWax and DB-FFAP) gas chromatography. All phases are dipolar, strongly hydrogen-bond basic with no hydrogen-bond acidity and of moderate cohesion. No two phases are exactly alike, however, and selectivity differences identified with cavity formation and dispersion interactions, n- and pi-electron pair interactions, dipole-type interactions and hydrogen-bond interactions are quantified by differences in the system constants at a fixed temperature where retention occurs solely by gas-liquid partitioning. The system constants vary linearly with temperature over the range 60-140 degrees C (except for n- and pi-electron pair interactions which are temperature invariant) facilitating a general comparison of the importance of temperature on selectivity differences for compared phases. From a mechanistic point of view it is demonstrated that selectivity differences can result from chemical differences between the poly(ethylene glycol) stationary phases and from differences in the relative contribution of interfacial adsorption to the retention mechanism. The latter depends on both system properties and solute characteristics.
溶剂化参数模型用于研究填充柱（Carbowax 20M）和熔融石英开管柱（HP - 20M、AT - Wax、HP - INNOWax和DB - FFAP）气相色谱中聚乙二醇固定相选择性的差异。所有固定相均为偶极的，具有强氢键碱性，无氢键酸性且内聚能适中。然而，没有两个固定相完全相同，通过空穴形成和色散相互作用、n - 和π - 电子对相互作用、偶极型相互作用以及氢键相互作用所确定的选择性差异，在固定温度下通过系统常数的差异进行量化，此时保留仅通过气液分配发生。系统常数在60 - 140℃范围内随温度呈线性变化（n - 和π - 电子对相互作用除外，其与温度无关），这便于对温度对所比较固定相选择性差异的重要性进行总体比较。从机理角度证明，选择性差异可能源于聚乙二醇固定相之间的化学差异以及界面吸附对保留机理相对贡献的差异。后者取决于系统性质和溶质特性。
