分子电性距离矢量用于多溴联苯醚分子结构表达及色谱保留时间预测

应用分子电性距离矢量(MEDV)对多溴联苯醚(PBDEs)的209种同系物进行结构表征.通过多元线性回归的方法,建立了PBDEs定量结构-色谱保留(QSRR)关系的6个变量和5个变量的两种模型.两种模型的建模计算值复相关系数R均为0.995;用留一法(LOO)进行了交互检验,其复相关系数(R2cv)分别为0.987和0...     

5种甲氧基多溴联苯醚与羟基自由基的二级反应速率常数的测定及反应活性分析

测定了水环境中检出的4’-MeO-BDE-17,5-MeO-BDE-47,5’-MeO-BDE-99,6-MeO-BDE-47和6-MeOBDE-85 5种甲氧基多溴联苯醚(MeO-PBDEs)与羟基自由基(·OH)反应的二级速率常数(k_(OH))。以BDE-47为参比化合物,采用竞争动力学方法测定MeO-PBDEs的k_(OH)。5种MeO-PBDEs的k_(OH)值在(0.531～1.030)×10~(10)L/(mol·s)范围内,5号位置甲氧基取代可以增大母体BDE-47与·OH的反应活性,而6号位置甲氧基取代则降低了反应活性;五溴取代的5’-MeO-BDE-99和6-MeO-BDE-85与·OH反应活性分别是四溴取代的5-MeO-BDE-47和6-MeO-BDE-47与·OH反应活性的1.1和1.9倍。MeO-PBDEs与·OH的反应活性受甲氧基和溴取代模式影响显著。     

MSPD-GC-ECD测定血液中甲氧基多溴联苯醚

以MSPD为萃取方法,GC-ECD为检测手段,建立了血液中痕量Me O-PBDEs的分析方法。通过对萃取材料、洗脱液、洗脱液体积和样品预处理的影响研究,确定了最佳分析条件:液氮研磨血液样品,ENVI-18为萃取材料,2 mL乙酸乙酯为洗脱液。在该条件下,应用于血液痕量MeO-PBDEs的测定,相对标准偏差小于10%,显示出良好的重复性;方法的检出限为0. 28～0. 62 ng/g,加标回收率在80. 2～117. 9%。结果表明,所建立的分析方法适合于血液中痕量MeO-PBDEs的检测。     

多溴联苯醚光化学降解

多溴联苯醚(PBDEs)是一类全球性的有机污染物,近年来由于其持久性、毒性和潜在的生物蓄积性而备受关注.光化学降解是环境中多溴联苯醚的重要归趋之一.本文综述了有机溶剂、水相和固相等不同介质中人工紫外光源和太阳光下PBDEs的光降解研究成果,不仅介绍了光源、反应介质、溴取代数目和取代型式对PBDEs光解速率和光解产物的影响,也包括了基于PBDEs光解的定量结构-性质关系,并展望了环境中PBDEs光化学行为的研究前景.     

苯乙酮衍生物气相色谱QSRR及其保留机理研究

以色谱热力学理论为基础,选取影响化合物色谱保留的分子结构和性质描述符号,采用MOPAC2000V1.3半经验分子轨道化学计算软件包PM3哈密顿函数算得的量化及物化参数,通过有进有出的逐步回归分析方法建立了苯乙酮衍生物在OV系列固定相上的气相色谱QSRR方程。所建立的多元回归方程相关系数均大于0.99。根据所建立的QSRR方程对苯乙酮衍生物的色谱保留机理进行了解释。     

食品中多溴联苯醚残留的气相色谱-串联质谱分析方法研究

建立了食品中8种多溴联苯醚(PBDEs) 残留的气相色谱-串联质谱分析方法,初步解析了PBDEs的电子轰击串联质谱(EI MS/MS)图,为各种目标物的准确定性分析提供依据.以BDE-28、BDE-47、BDE-66、BDE-85、BDE-99、BDE-100、BDE-153、BDE-154为研究对象,对EI MS/MS各分析参数进行了优化.用超声提取-酸性硅胶层析柱净化的前处理方法制备样品,当空白样品的加标水平为10.0、25.0 μg/kg时,8种PBDEs的平均加标回收率为82% ～112%,相对标准偏差为3.1% ～15%,方法检出限均低于1.5 μg/kg;8种PBDEs的线性范围为10.0 ～500 μg/kg,相关系数均大于0.994 7.     

气相色谱-负离子化学源-质谱法分析禽蛋食品中10种多溴联苯和多溴联苯醚残留

建立了气相色谱-负离子化学源-质谱法(GC-NCI-MS)同时分析禽蛋食品中10种多溴联苯(PBBs)和多溴联苯醚(PBDEs)残留的分析方法。禽蛋食品用正己烷超声提取、浓硫酸酸化、中性和酸性硅胶层析柱净化和正己烷洗脱后,以PCB209为内标物,采用GC-NCI-MS的选择离子监测方式(SIM)分析;同时探讨了目标物PBDE100 NCI-MS特征离子的断裂机理。当禽蛋食品空白的加标质量浓度为5(3.5)和50(35)μg/kg时,加标回收率为75.2%～107%,相对标准偏差为2.3%～8.8%,方法检测限为0.14～0.39μg/kg,线性范围为1～250μg/kg,相关系数皆大于0.9991,方法已用于禽蛋食品中10种痕量PPBs和PBDEs残留的同时分析。     

气相色谱柱对多溴联苯醚分析的影响

基于气相色谱-电子捕获检测器法对11种代表性多溴联苯醚进行分析,考察不同类型气相色谱柱对多溴联苯醚分离分析的影响. 结果表明:色谱柱极性是影响分离和响应的主要因素,极性较大的固定相上多溴联苯醚各单体的保留时间变长,响应降低,尤其是高取代多溴联苯醚的响应受到的影响最大. 柱长较短、液膜较薄的色谱柱有助于高取代多溴联苯醚的分析. 不同品牌的色谱柱受生产工艺的影响,对多溴联苯醚的响应产生较大影响.     

热解分离-气相色谱-质谱联用法测定聚苯乙烯电器外壳中20种多溴联苯和多溴联苯醚

将聚苯乙烯(PS)电器外壳样品预先加工制成能通过1mm筛的细颗粒。取此颗粒样品0.5mg置于样品杯中,在裂解仪上从100℃开始,以20℃·min~(-1)的速率升温至340℃,热解60s,使所测定的20种多溴联苯(PBBs)和多溴联苯醚(PBDEs)热解析出,随即引入DB-1色谱柱,以氦气为载气,在分流进样、程序升温的条件下进行色谱分离,并在电子轰击离子源(EI)和选择离子监测(SIM)模式下进行质谱(MS)测定。上述20种被测物均在100～2 000mg·kg~(-1)内与其对应的峰面积呈线性关系,其检出限(3S/N)均小于15mg·kg~(-1)。在3个浓度水平上进行加标回收试验,测得回收率在77.9%～119%之间,测定值的相对标准偏差(n=7)均小于20%。按此方法分析了3件实样,并用标准方法 GB/T 26125-2011附录A进行对比,结果表明此方法的测定结果与标准方法的测定结果基本一致。     

Gas chromatographic retention of 180 polybrominated diphenyl ethers and prediction of relative retention under various operational conditions

The gas chromatographic (GC) retention times of 180 polybrominated diphenyl ethers (PBDEs) were obtained under different operational conditions on two types of commonly used capillary columns, Restek Rtx-1614 and J&W DB-5MS, of different dimensions. The relative retention times (RRTs) for PBDEs were calculated by normalizing the retention times of individual congeners to the sum of those of BDEs 47 and 183. In clear contrast to polychlorinated biphenyls (PCBs), the elution of PBDEs has few cross-homolog overlaps, and this observation is discussed in terms of molecular conformation with regard to co-planarity. Within a homolog, ortho substitution in PBDEs tends to decrease GC retention, and such an effect is stronger for higher homologs. With the RRT database established in this work, a simple approach is evaluated for the identification of all mono to hepta PBDEs from the RRTs of 39 congeners under various GC conditions to facilitate the identification of unknown PBDE peaks for which chemical standards are not available.     

应用分子全息QSAR预测多溴二苯醚(PBDEs)的毒性

多溴二苯醚(PBDEs)可能会激活芳香烃受体的信号传导通路, 从而对人类和野生动物的健康产生负面影响. 鉴于多溴二苯醚实验毒性数据有限, 发展基于结构的化合物毒性预测模型具有重要的实际意义. 本文基于一种新的分子结构表征方法—— 分子全息, 研究了18种多溴二苯醚结构与毒性之间的关系, 建立了相关性显著、稳健性强的QSAR模型(r²= 0.991, q²_LOO= 0.917). 随机选出14种多溴二苯醚为训练集, 其他4种化合物为测试集以验证分子全息QSAR模型的稳健性和预测能力. 结果在最佳建模条件下得到模型的统计参数如下：r² = 0.988, q²_LOO = 0.598, r²_pred = 0.955, 预测值与实验值之间的均方根误差(RMSE)为0.155. 这表明基于分子全息的QSAR模型可以对多溴二苯醚毒性进行比较准确的预测. 本文同时利用分子全息QSAR模型色码图, 探讨了影响多溴二苯醚毒性的分子结构特征及分子机理.     

烯烃气相色谱保留指数的QSRR研究

通过对184个烯烃类化合物在不同固定相不同柱温下的617个样本的气相色谱保留指数值(RI)与其部分参数:拓扑指数(mQ)、偶极矩(DPL)、固定液极性值(CP)及柱温(T)建立定量-色谱保留相关(QSRR)模型.分别利用多元线性回归(MLR)、偏最小二乘回归(PLSR)、人工神经网络(ANN)建模,同时采用内部及外部双重验证的办法对所得模型稳定性能进行深入分析和检验,建模计算值、留一法(LOO)交互检验(CV)预测值和外部样本的复相关系数Rcum,QLOO和Rext分别为0.999 2,0.998 4和0.999 2(MLR);0.999 0,0.998 0和0.999 1(PLSR);0.999 4,0.998 7和0.999 2(ANN).结果表明:所建定量结构保留关系(QSRR)模型具有良好的稳定性和预测能力,较好地揭示了烯烃类化合物在不同固定相不同柱温上气相色谱保留指数的变化规律.     

A cleanup method of serum extracts with molecular sieves as SPE sorbents for the analysis of polybrominated diphenyl ethers

Based on the size- and shape-selective sorption, 13X molecular sieves were developed as solid-phase extraction adsorbents to cleanup serum extract for the determination of polybrominated diphenyl ethers. The important parameters affecting the cleanup efficiency were investigated including the amount of sorbents, the type, and volume of solvents. Under the optimized conditions, the capacity for removing impurities was evaluated via gel permeation chromatography and gas chromatography with mass spectrometry. The results demonstrated that up to 99% of lipids in corn oil (13 mg) can be removed after cleanup, and endogenous compounds in serum can also be effectively eliminated. The cleanup efficiency is not only superior to hydrophile-lipophile balance column, but also close to acid silica gel and multifunction impurity sorbents. Generally, the developed cleanup method exhibited higher recovery for polybrominated diphenyl ethers with more than four bromines, especially for nona- and deca-brominated diphenyl ethers (99.1˗117.8%). The cleanup method can be coupled with gas chromatography and tandem mass spectrometry for polybrominated diphenyl ethers analysis in human serum. The method detection limits were 0.01˗0.27 ng/mL and average recovery was 50.9˗113.3%, except 2,3',4',6-tetrabrominated, 2,3',4,4',6-pentabrominated, and 2,3,3',4,4',5',6-heptabrominated diphenyl ethers. 2,2',4,5'-Tetrabrominated diphenyl ethers had the highest detection frequency (95%) in human serum, whereas decabrominated diphenyl ethers had the maximum mean concentration (0.50 ng/mL).     

QSPR study on GC relative retention time of organic pesticides on different chromatographic columns

In the present study, Lu index and distance-based atom type topological index (DAI) previously developed in our team, were introduced and combined with molecular electronegativity chi ep to characterize quantitative structure-property relationship of GC relative retention time (RRT) for several types of structurally diverse organic pesticides on the four kinds of chromatographic columns. Using multiple linear regression technique, four several-variable models are obtained with the estimations correlation coefficient (R(2)) being between 0.9655 and 0.9285, and the correlation coefficient (R(2)cv) in the leave-one-out cross-validation procedure are between 0.9560 and 0.9143, respectively. The results in this study indicate that the three topological indices Lu index, DAI, and molecular electronegativity chi ep can predict the gas chromatographic RRT of organic pesticides with diverse hetero-atoms.     

多环芳香硫化合物的定量结构-气相色谱保留指数关系

应用分子电性距离矢量(MEDV)对114个多环芳香硫化合物(PASHs)进行结构表征,通过多元线性回归建立了PASHs的气相色谱保留指数与MEDV参数之间的定量结构-保留值关系模型;同时采用逐步回归分析进行变量筛选,继而以留一法交互检验对所得优化模型进行预测能力评价,所建立的模型的相关系数为0.9947,交互检验相关系数为0.9940,表明该优化模型具有良好的稳定性和预测能力。此外,通过将样本集按2:1分成校准集和测试集预测,统计分析结果显示所建的模型具有良好的相关性和稳定性。本文所建的定量结构-保留值关系(QSRR)模型为预测PASHs的气相色谱保留指数提供了一个便捷有效的新方法。     

A QSRR Study on the Chromatographic Retention Indices of Hydroxylated Polychlorinated Biphenyls

Hydroxylated Polychlorinated Biphenyls (HO-PCBs) are the metabolite of polychlorinated biphenyls and have drawn much attention because they have hazard on human health and ecosystems. Molecular connectivity index calculation has been performed for 19 HO-PCB compounds. A number of statistically based parameters have been extracted. Linear relationship between chromatographic retention index (RI) and the molecular connectivity index of 15 compounds in the training set has been established by multiple linear regression method. The other 4 HO-PCBs are used as the external test set. The result shows that the parameters can be well used to express the quantitative structure-retention relationship (QSRR) of HO-PCBs. Good stability and predictive ability have been demonstrated by leave-one-out cross-validation and the external test set.     

Mass spectrometric characteristics of decabromodiphenyl ether and the application of isotopic dilution in the electron capture negative ionization mode for the analysis of polybrominated diphenyl ethers

The mass spectrometric properties of (12)C-and (13)C-labeled decabromodiphenyl ether (BDE-209) in the low-resolution mass spectrometry electron capture negative ionization mode (ECNI-MS) is described in detail and are compared with those of polybrominated diphenyl ethers (PBDEs) with a lower degree of bromination. The mass spectrometric properties of BDE-209 make it possible to apply (13)C-labeled BDE-209 as an internal surrogate standard for the determination of BDE-209 by isotopic dilution. A combination of the [Br](-) and [C(6)Br(5)O](-) fragment ions is proposed for the detection with ECNI-MS in the selected ion monitoring mode to increase selectivity, sensitivity and accuracy in the determination of decabromodiphenyl ether together with other polybrominated diphenyl ethers. The importance of optimizing the instrument parameters to obtain optimal response from the mass spectrometer in the analysis of PBDEs is discussed in detail.