Prediction of retention indices. V. Influence of electronic effects and column polarity on retention index.
Prediction of retention indices. V. Influence of electronic effects and column polarity on retention index.
复制标题
保留指数的预测。
DOI：
10.1016/s0021-9673(00)00901-8
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Peng,CT
中科院分区：
文献类型：
--
作者：
Peng,CT
对于1-卤代-正烷烃，将亚甲基添加到分析物分子的保留指数增量显示为不同于100 i.u.，根据保留指数预测中的当前惯例通常分配的值。在程序升温气相色谱法中，线性内插保留指数I，以分子中原子数Z为变量的线性回归方程I=AZ+（GRF），可描述16个同系物在非极性和极性色谱柱上的保留，其特征值分别为线性回归系数A和基团保留因子GRF。提出了一个基于电子密度和相对于正构烷烃的电子密度分布的分子滞留模型。该模型将分析物分子中的分子间和分子内电子效应及其与固定液相的偶极-偶极相互作用表现为A值的变化。（GRF）值随着官能团的连接能力而变化，用于扩展的共轭、取代等，但受与固定液相的氢键（H-键合）的影响最大。人们可以从上述方程右侧的三个参数中的任何两个估计有机化合物混合物的洗脱顺序，或者从A和（GRF）值检索整个同源系列的保留指数。每个分析物分子在不同色谱柱上具有其自身的A值这一事实使得色谱柱差异（ΔI）是化合物特异性的，而不是色谱柱特异性的，这与先前的假设不同。
The retention index increment for addition of a methylene group to an analyte molecule is shown for 1-halo-n-alkanes to be different from 100 i.u., a value that is customarily assigned according to the current convention in retention index prediction. In temperature-programmed gas chromatography using linearly interpolated retention index I, a linear regression equation, I=AZ+(GRF), with the number of atoms (Z) in the molecule as variable can describe the retention of 16 homologous series of organic compounds on non-polar and polar columns with characteristic A (linear regression coefficient) and (GRF) (group retention factor) values. A molecular model of retention on the basis of electron density and electron density distribution relative to that of n-alkane is proposed. This model brings out the inter- and intramolecular electronic effects in the analyte molecule and its dipole–dipole interaction with the stationary liquid phases, as variations in the A value. The (GRF) value varies with the connectivity ability of a functional group for extended conjugation, substitution, etc., but is most influenced by hydrogen bonding (H-bonding) with the stationary liquid phase. One can estimate the sequence of elution of a mixture of organic compounds from any two of the three parameters on the right-hand side of the above equation or retrieve the retention indexes of an entire homologous series from its A and (GRF) values. The fact that each analyte molecule has its own A value on different columns makes column difference (ΔI) compound-specific rather than column-specific, a departure from previous assumptions.