土壤中邻苯二甲酸酯气相色谱保留分异及其构效关系

Differentiation of gas chromatographic retention and structure-property relationship of phthalate acid esters in soil

本文选择典型HP-5MS色谱柱和选择离子扫描模式(SIM),通过不同土壤加标回收验证和分析参数调节,优化建立了适用于土壤中邻苯二甲酸酯(PAEs)的气相色谱-质谱联用(GC-MS)检测分析方法,揭示了PAEs色谱保留分异特征;结合PAEs主要电子结构和热力学性质的量子化学Hartree-Fock计算,由偏最小二乘(PLS)分析方法成功发展了PAEs色谱保留分异的定量结构-性质相关关系(QSPR).研究结果显示,GC-MS分析方法对土壤中酞酸酯的平均回收率在70.64%—119.80%之间,相对标准偏差为0.23%—16.45%,表明其对不同土壤中PAEs的分析测定具有较好适宜性.QSPR对色谱保留分异的调整累积解释方差R2y,cum(adj)达0.968,累积交叉验证相关系数Q2cum和外部预测相关系数Q2EXT分别为0.941与0.854,表明模型具有较好的稳定性和预测性能,可满足PAEs未知色谱保留行为准确预测和定性识别的要求.QSPR分析表明,PAEs分子的极化率及其与弱极性固定相分子间的色散作用是主导其色谱保留分异与变化的重要结构因子,而PAEs的热力学稳定性越强,热运动越慢,越可能极大促进PAEs在色谱固定相表面通过色散而非化学作用介导的吸附过程,延长色谱保留时间.这对环境中PAEs的分析与鉴定具有重要的科学意义.

Based on the validation of spiked soils recovery and optimization of analytical parameters,a gas chromatography mass spectrometry（ GC-MS） equipped with a HP-5 MS column and selective ion monitoring（ SIM） mode was developed for the determination of PAEs in soils. Differentiation ofgas chromatographic retention of PAEs was revealed at the same time. By combiming the quantum Hartree-Fock calculations of the major electronic structures and thermodynamic properties of PAEs,a quantitative structure-property relationship（ QSPR） of chromatographic retention of PAEs was successfully developed by partial least squares（ PLS） analysis. The results showed that the average recoveries of the PAEs in soils were in the range of 70. 64% to 119. 80% with relative standard deviations of 0.23% to 16.45%,which indicated high applicability to the determination of the PAEs in different soils. The cumulative interpretation variance of QSPR for chromatographic retention differentiation was up to 0.968,and the correlation coefficients given by cumulative cross-validation and external prediction were 0.941 and 0.854,respectively. The optimized QSPR was shown to be highly robust and predictive, which could meet the requirements of accurate prediction and qualitative identification of unknown chromatographic retention of PAEs. Furthermore,the analysis of QSPR indicated that the polarizability of PAEs and the latent dispersion interaction with the molecules of weakly polar stationary phase were the important structural factors,which were believed to dominate the differentiation and variation of gas chromatographic retention. The stronger the thermodynamic stability of PAEs,the slower the thermal motion,the more likely it is that PAEs are adsorbed on the surface of the chromatographic stationary phase by dispersion rather than chemical action,and the chromatographic retention times of PAEs are further extended.