氯酚为前生体生成二噁英类的研究进展

评述了氯酚作为前生体生成二噁英类的问题，总结了热过程、光转化、酶反应三种途径中氯酚生成二噁英类的条件及机制。热过程中氯酚缩合成二Wu英的主要影响因素为：温度、热解时间、含氧量和催化剂；而光转化过程中光强、溶剂种类、光敏物质的存在对氯酚生成Wu英有影响，热过程和光转化的反应机制均是通过自由基来完成的。     

二(噁)英提取方法的比较

二(噁)英是一类氯化多核芳香化合物的总称,可以分为多氯代二苯并二(噁)英(polychlorinated dibenzo -P-dioxins,简称PCDDs)和多氯代二苯并呋喃(polychlorinated dibenzofurans,简称PCDFs),根据取代氯原子的不同位置,共有75种PCDDs和135种PCDFs,由于其2,3,7,8四个取代位置均有氯原子的PCDDs和PCDFs具有致畸变、致突变和潜在致癌作用,已经引起了世界各国环境科学家甚至于公众的关注.     

同位素稀释气相色谱/三重四极质谱法测定二(噁)英同类物

建立了同位素稀释气相色谱/三重四极质谱法测定17种2,3,7,8位氯取代的二(噁)英同类物的痕量分析方法.使用Agilent 7000B三重四极气质联用仪,通过对色谱、质谱条件的优化,建立了高灵敏度和高选择性的二(噁)英同类物分析方法,17种二(噁)英毒性同类物的平均相对响应因子的相对标准偏差均小于11％;校正曲线在0...     

Improved Method for the Determination of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans (PCDD/Fs) in Sanitary Napkins

Abstract

An improved method was developed for determining highly toxic 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD/Fs) in sanitary napkins. Samples were extracted by Soxhlet (50% dichloromethane/hexane) and sonication (hexane), and a multi-layer silica column was used for clean-up after acetone precipitation to separate the superabsorbent polymers. Improved separation efficiency of PCDD/Fs from sanitary napkins with a high level of superabsorbent polymers was achieved using the acetone precipitation method. Hexane was then applied as an alternative solvent to remove residual interfering substances including sticky components contained on sanitary napkins via alumina column chromatography in the second clean-up step. Recoveries approached 100% with an average relative standard deviation of less than 15%, and recoveries of internal standards were from 70.5 to 114.8% and 0.6 to 13.6% for the two extraction methods. The mean method detection limit was 0.075–0.968?pg/g for Soxhlet extraction and 0.0032–0.091?pg/g for sonication extraction. The established method meets the quality criteria for the screening of dioxins stated in EU Regulations 589/2014 and 709/2014, and therefore provides a suitable alternative for the determination of dioxins in sanitary napkins containing superabsorbent polymers.     

HRGC-LRMS测定垃圾焚烧炉布袋飞灰中的二噁英类物质

利用高分辨气相色谱-低分辨质谱(HRGC-LRMS)测定了某垃圾焚烧厂布袋飞灰中的二(口恶)英类物质,结果表明对于测定二(口恶)英类浓度相对较高的垃圾飞灰而言,采用HRGC-LRMS是一种可行的方法,回收率在74％～114％之间。该飞灰样品中以二(口恶)英为主,呋喃的含量相对较低,二(口恶)英／呋喃值为4.6,二(口恶)英类物质总量为211.7ng／g,折算到毒性当量为0.69ngI-TEQ／g。     

高分辨气相色谱/质谱法分析新闻纸和复印纸中的二(口恶)(口英)

随机选择空白的和经过印刷的新闻纸和复印纸,粉碎后用溶剂提取并经多步色谱柱纯化,采用同位素稀释、高分辨气相色谱/高分辨质谱(HRGC/HRMS)联用技术分析了其中的二(口恶)(口英)含量.结果表明:新闻纸中二(口恶)(口英)的总量高于复印纸,但是毒性当量却低于复印纸;经过印刷的新闻纸和复印纸中二(口恶)(口英)的含量均高于空白的新闻纸和复印纸;新闻纸和复印纸中相同二(口恶)(口英)异构体的含量是不同的.空白的和经过印刷的新闻纸中二(口恶)(口英)毒性当量分别为0.48 ng/kg和0.61 ng/kg,而空白的和经过印刷的复印纸中二(口恶)(口英)毒性当量分别为0.74 ng/kg和0.79 ng/kg.所有样品中添加的13C标记的2,3,7,8位取代的二(口恶)(口英)回收率均在49.82%至131.34%之间.     

高分辨气相色谱/质谱法分析新闻纸和复印纸中的二噁

随机选择空白的和经过印刷的新闻纸和复印纸 ,粉碎后用溶剂提取并经多步色谱柱纯化 ,采用同位素稀释、高分辨气相色谱 /高分辨质谱 (HRGC/HRMS)联用技术分析了其中的二含量。结果表明 :新闻纸中二的总量高于复印纸 ,但是毒性当量却低于复印纸 ;经过印刷的新闻纸和复印纸中二的含量均高于空白的新闻纸和复印纸 ;新闻纸和复印纸中相同二异构体的含量是不同的。空白的和经过印刷的新闻纸中二毒性当量分别为 0 4 8ng/kg和 0 6 1ng/kg,而空白的和经过印刷的复印纸中二毒性当量分别为 0 74ng/kg和 0 79ng/kg。所有样品中添加的13 C标记的 2 ,3,7,8位取代的二回收率均在 4 9 82 %至 131 34%之间。     

高分辨气相色谱/质谱法分析新闻纸和复印纸中的二恶英

随机选择空白的和经过印刷的新闻纸和复印纸,粉碎后用溶剂提取并经多步色谱柱纯化,采用同位素稀释、高分辨气相色谱/高分辨质谱(HRGC/HRMS)联用技术分析了其中的二含量。结果表明:新闻纸中二的总量高于复印纸,但是毒性当量却低于复印纸;经过印刷的新闻纸和复印纸中二的含量均高于空白的新闻纸和复印纸;新闻纸和复印纸中相同二异构体的含量 是不同的。空白的和经过印刷的新闻纸中二毒性当量分别为0.48 ng/kg和0.61 ng/kg,而空白的和经过印刷的复印纸中二恶英毒性当量分别为0.74 ng/kg和0.79     

Structural factors affecting Aryl Hydrocarbon Hydroxylase induction by Dibenzo-p-dioxins and Dibenzofurans

Quantitative structure-activity relationships have been developed to rationalize the experimental data obtained with a series of dibenzo-p-dioxins and dibenzofurans in the assays for receptor binding and aryl hydrocarbon hydroxylase (AHH) induction. Lateral substituents (in positions 2, 3, 7, and 8 of the tricyclic system) do not affect receptor binding and AHH induction in the same manner. Various hypotheses are suggested to explain this finding. Of special interest is the possibility that the lateral substituents are directly involved in the mechanism which transforms the receptor to the active state. The implications of this possibility are considered with regard to the design of an antidote for poisoning caused by the chlorinated congeners which occur as contaminants in certain commercial products.     

SIM/GC/ITD测定土样中ppt级多氯二苯并二噁英

本文介绍了以选择离子检测方式的气相色谱-离子阱检测器(SIM/GC/ITD)分析土样中ppt级多氯二苯并-对-二噁英的方法。该法所用仪器简单,操作简便,净化效率和回收率高。当组分浓度在ppt～ppb范围、母体组成在很大范围变动时,也有较好的重复性。     

“永固紫”染料和四氯苯醌中多氯代二苯并二噁/呋喃的分析

采用浓硫酸对5种不同来源的四氯苯醌和“永固紫”染料样品进行溶解分散,用甲苯提取和多层色谱柱纯化,利用同位素稀释法及高分辨气相色谱质谱(HRGCHRMS)联用技术,测定了其中的多氯代二苯并二口恶口英呋喃(PCDDF)的质量比。结果表明“永固紫”染料及其原料中PCDDF的质量比异常高,八氯代二苯并二口恶口英呋喃(OCDDF)已达到μgg级甚至100μgg级,七氯代二苯并二口恶口英呋喃(HpCDDF)和六氯代二苯并二口恶口英呋喃(HxCDDF)质量比也达到ngg级。所有样品的毒性当量浓度(TEQ)均已超过10pgg的危险水平,是纺织品中PCDDF的一类重要污染源。并进一步探讨了PCDDF的来源。     

同位素稀释的气相色谱/高分辨质谱联用测定食品中二噁英和共平面多氯联苯

采用HRGC/HRMS和同位素稀释定量技术对样品中17种4~8个氯原子取代的二噁英和呋喃(PCDDs/Fs)与12种共平面多氯联苯(PCBs)定量分析。样品经索式抽提、FMSPowerPrep系统净化、浓缩,利用高分辨气相色谱/高分辨质谱联用仪的多离子检测方式,同位素稀释技术对样品中的目标化合物进行定性和定量。该方法的检出限为pg/g水平。13C同位素内标回收率范围为47%~100%。对3个CRM鱼样中17个PCDDs/Fs和4个PCBs的检测值均在标准定值允许误差范围内。对5个不同的实际样品鱼进行测定表明,样品的回收率在48%~100%之间,回收率的相对标准偏差小于20%;对同一样品进行定量检测的精密度测试结果表明,17种PCDDs/Fs浓度的RSD低于16%,12种PCBs浓度的RSD低于11%。本方法定量分析重现性良好。     

New Cleanup Procedure for Determining Polychlorinated Dibenzo-P-Dioxins and Dibenzofurans in Lipophilic Matrices

Abstract

A new cleanup procedure for determining polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in naturally occurring adipose matrices is suggested. The procedure can be used for analyzing butter, human and cow's milk, eggs, and meat. Quality of sample purification is better than that in the standard procedure, and the recovery of PCDD and PCDF internal standards is within the range 50–80%. The time it takes for sample preparation is shortened, and the consumption of solvents and sorbents is decreased. The FAS-MD activated carbon, which was especially prepared for the extraction of dioxins and related compounds, was used in this work.     

多氟代、多氯代和多溴代二苯并对二噁英化合物的一些性质的比较研究

采用密度泛函理论(DFT)方法, 在B3LYP/6-311G**和B3LYP/6-31G*两种水平上, 对76种多氟代二苯并对二噁英系列化合物(PFDDs)进行了几何构型的全优化, 并计算了各分子在298.15 K, 1.013×10⁵ Pa的标准状态下的热力学参数. 基组从6-31G*增大到6-311G**没有显著改变标准生成热(Δ_fH^?)、标准生成自由能(Δ_fG^?)和标准熵(S^?)数值. 根据B3LYP/6-311G**水平计算得到的Δ_fG^?的相对大小, 求得PFDDs同数目取代氟原子的各异构体的相对稳定性的顺序. 采用基团贡献法计算了多溴代二苯并对二噁英(PBDDs)、多氯代二苯并对二噁英(PCDDs)和PFDDs的辛醇-水分配系数(lg K_ow). 并将PFDDs的Δ_fH^?, Δ_fG^?, S^?和lg K_ow的计算结果与PBDDs和PCDDs的相关数值进行了比较. 同时, 计算了PFDDs各组异构体化合物的生成反应相对速率常数, 采用统计热力学程序计算了这些化合物在200至1800 K的恒压摩尔热容(C_p,m), 并用最小二乘法求得C_p,m与温度之间的相关方程, 发现C_p,m与T, T^－1和T^－2之间有着很好的相关性.     

Solid Surface Room Temperature Phosphorescence of Polychlorinated Dibenzofurans Enhanced by a Surface Active Agent

Abstract

Room temperature phosphorescence characteristics on filter paper of dibenzofuran (DF) and several polychlorinated dibenzofurans (PCDFs) in the presence of different heavy atoms in conjunction with a surface active agent, sodium lauryl sulfate (NaLS), have been studied. The use of this surfactant produces an enhancement of the phosphorescence intensity in all the cases studied, which improve the sensitivity in the determination of DF and PCDFs. The optimization of experimental conditions like type of filter paper, drying and cooling times of the filter paper after spotting the sample, irradiation time, concentration of heavy atom and concentration of surfactant has been carried out. Phosphorescence lifetimes, linear dynamic range, relative standard deviation and limit of detection of the different compounds were also determined.     

Quantum Chemical Investigation of Polychlorinated Dibenzodioxins,Dibenzofurans and Biphenyls: Relative Stability and Planarity Analysis

All the possible polychlorinated aromatic compounds in the classes of dibenzodioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) were studied by the quantum chemical methods of HF/6-311++G(d,p), B3LYP/6-311++G(d,p), and MP2/cc-pVTZ. The calculated stabilities and structures of these compounds were compared with the available data on their abundance and toxicity. Prediction models for trends in energy and planarity among these congeners were proposed. The results discussed here can help contribute to the understanding of the role of dioxin-like compounds (DLCs) in the environment.     

Problems in the Determination of Polychlorinated Biphenyls

The presence of aromatic hydrocarbons in pesticide-grade hexanes affects the elution patterns of polychlorinated biphenyls (PCB) and chlorinated hydrocarbon pesticides from silicic acid columns. Several batches of silicic acid Silicar® (Mallinckrodt) were contaminated with 0.031–0.163 mcg/g of PCB expressed as Aroclor® 1254. Chlorinated naphthalenes accompany PCB on silicic acid chromatography and their presence can be detected from an absorption maximum at 306 nm, A^1% _1cm = 329. PCB of the Aroclor® 1254 type were detected in American eel (Anguilla rostrata), herring (Clupea harengus), and Atlantic salmon (Salmo salar) in concentrations of 0.63–0.75, 0.32–0.54, and 0.45 mcg/g wet weight, respectively. Commercial fish oil contained 3.55 mcg/g of PCB.     

Solid Phase Extraction of Polychlorinated Dibenzo-<Emphasis Type="Italic">p</Emphasis>-dioxins,Dibenzofurans, and Dioxin-like Polychlorinated Biphenyls from Fats

A new method for determination of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls in fats based on the use of Carboxen 1000 and 1016 sorbents has been proposed. The use of Carboxen 1000 obviates the stage of chemical degradation of the fat matrix, thus providing high quality of the extract purification at shorter sample preparation times and a relatively small solvent consumption. The recovery values were slightly lower than in common methods of sample preparation but, nonetheless, conformed to the criteria of Russian and foreign standard methods. The method can be used to analyze animal fats and vegetable oils from food and animal feeds.