Liu Fengping, Liang Yizeng, Cao Chenzhong, Zhou Neng
School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201, PR China.
Anal Chim Acta. 2007 Jul 2;594(2):279-89. doi: 10.1016/j.aca.2007.05.023. Epub 2007 May 21.
For the retention index of polar compounds, polar groups in molecules would participate in polar interactions between eluents and stationary phases and thus would be expected to make large and separate contributions to the total retention index (RI). The characterization of the structural feature will help to elucidate the quantitative structure-retention relationship (QSRR). In this paper, on the basis of the PEI index previously developed by Cao, two novel molecular polarizability effect index, modified molecular polarizability index (MPEI(m)) and modified inner molecular polarizability index (IMPEI(m)) were proposed to predict the GC retention of a variety of oxygen-containing organic compounds with diverse chemical structures on OV-1 and SE-54 stationary phases. The sets of molecular descriptors were derived directly from the structure of the compounds based on graph theory. Simple linear regression equations between the RI and the topological indices were established for each stationary phase separately (R>0.99). Statistical analysis showed that the QSRR models have high internal stability and good predictive ability for external groups. The molecular properties known to be relevant for GC retention data, such as molecular size, branching and polar functional groups were well covered by the generated descriptors. The models with topological indices were compared with those based on quantum-chemical descriptors. It is observed that topological indices produce better correlations with Kovat's retention index. The results indicate the efficiency of presented indices in the structure-retention index correlations of complex compounds with polar multi-functional groups.
对于极性化合物的保留指数，分子中的极性基团会参与洗脱剂与固定相之间的极性相互作用，因此预计会对总保留指数（RI）做出较大且独立的贡献。结构特征的表征将有助于阐明定量结构-保留关系（QSRR）。本文在曹之前开发的PEI指数的基础上，提出了两种新的分子极化率效应指数，即修正分子极化率指数（MPEI(m)）和修正内部分子极化率指数（IMPEI(m)），以预测多种化学结构各异的含氧有机化合物在OV-1和SE-54固定相上的气相色谱保留情况。这些分子描述符集是基于图论直接从化合物结构中推导出来的。分别为每个固定相建立了RI与拓扑指数之间的简单线性回归方程（R>0.99）。统计分析表明，QSRR模型具有较高的内部稳定性和对外部基团良好的预测能力。所生成的描述符很好地涵盖了已知与气相色谱保留数据相关的分子性质，如分子大小、支化和极性官能团。将基于拓扑指数的模型与基于量子化学描述符的模型进行了比较。观察到拓扑指数与科瓦特保留指数具有更好的相关性。结果表明所提出的指数在具有极性多官能团的复杂化合物的结构-保留指数相关性方面的有效性。
