单光子电离质谱用于二噁英前生体检测

垃圾焚烧处理是二噁英的主要产生源之一,在二噁英的形成阶段会先形成氯苯、氯酚、多环芳烃等二噁英类前生体。这些前生体浓度较高,并且与二噁英类毒性当量存在密切关联。对前生体的在线检测研究已成为主要研究方向之一。本研究利用自制的纳秒真空紫外电离-飞行时间质谱仪,发展了一种快速测量气相条件下氯苯、多氯酚、萘等方法,并通过标准样测试对该方法进行了实验评估。对于氯苯标准样,在5~100μg/L范围内,用本方法获得的母体离子信号强度与浓度呈现良好的线性关系。     

PVC化学链燃烧过程中二噁英生成研究

制备了负载硅溶胶的CaSO₄载氧体,并对其与CH₄、CO和H₂的反应特性进行了研究表征。采用管式炉实验系统,对PVC在基于CaSO₄载氧体的化学链燃烧和空气燃烧两种方式下,二噁英的生成特性进行了实验研究。结果表明,负载了硅溶胶的CaSO₄载氧体与CH₄、CO和H₂反应均接近完全转化,其中,与CH₄和H₂的反应时间显著短于CO。采用化学链燃烧方式可有效抑制PVC燃烧过程二噁英的生成,其生成量和毒性当量分别由空气燃烧中的34 172.5 pg/g及732.8 pg(I-TEQ)/g降到化学链燃烧的2 270.9 pg/g及290.2 pg(I-TEQ)/g,这主要是因为化学链燃烧过程中燃料与O₂不直接接触,显著减少了大分子碳结构的氧化断裂以及HCl向Cl₂的转化,从而抑制了二噁英的低温从头合成反应和前驱物生成反应。     

红壤中痕量五氯酚的气相色谱法测定

五氯酚因其对生物体的广谱毒性和诱突变性，被我国和其他许多国家列为环境优先监测的持久性有机污染物之一。它在红壤地区曾广泛大量的使用，给环境造成一定的负面影响。本文探讨了应用超声波萃取、乙酸酐衍生化和气相色谱／电子捕获检测器(GC／ECD)测定红壤中痕量五氯酚的方法，并对不同的影响因素进行了对比，确定了一种较可靠的方法。该法的回收率为89％-101％。     

微生物群落对多氯酚的脱氯特性及机理研究

从正在运行的流化床生物反应器中分离出对三氯酚具有高效脱氯能力的微生物群落. 在含柠檬酸钛为氧化还原缓冲剂的合成培养基中研究了该群落的生理特性. 结果表明, 该微生物菌群可以利用丙酮酸为碳源和能源, 丙酮酸发酵、硫酸盐还原和脱氯反应三个过程严格地按顺序依次进行, 并且丙酮酸浓度在最初2 d内急剧下降, 同时有代谢产物乙酸、甲酸和氢气形成. 只有当硫酸盐被还原成硫化物后, 脱氯反应才会发生. 硫酸盐和钼酸盐的存在会强烈地抑制微生物的脱氯活性. 溴乙烷磺酸酯(BES)可以完全抑制微生物的产甲烷活性. 青霉素G(10 μg/mL)对该微生物菌群的脱氯作用没有抑制. 该微生物菌群按形态特征可以分为3类, 即弧菌、链球菌和杆菌. 利用荧光标记的16S和23S rRNA寡核苷酸探针进行原位杂交试验表明, 该微生物菌群中存在Proteobacteria的r亚类和δ亚类.     

木材及木制品中残留五氯酚的气相色谱测定法

建立了木材及木制品中五氯酚的气相色谱测定法.样品经丙酮提取,浓硫酸净化,正己烷萃取后吹干,于0.1 mol/L K2CO3的介质中用乙酸酐衍生,采用HP-5毛细管气相色谱柱分离, ECD检测器进行检测.在0.01～50 mg/L的范围内线性关系良好;检出限为0.005 mg/kg;相对标准偏差为2.6%～3.6%;回收率在89.3%～103.5%之间.方法具有灵敏、简便、准确的特点.     

五氯酚免疫层析检测试纸条的研究

利用胶体金免疫层析技术建立了一种快速检测五氯酚(PCP)残留的方法。采用柠檬酸三钠还原法制备大小一致、分布均匀、粒径为20 nm的胶体金颗粒,以此标记五氯酚抗体,制备金标抗体。将五氯酚包被抗原和羊抗鼠二抗分别结合于硝酸纤维膜上,依次将型号Millipore135硝酸纤维膜、型号VL78金标垫、型号SB06样品垫及吸水纸组装于PVC底板上,组装成胶体金免疫层析检测试纸条。通过试纸条上颜色的深浅,检测样品中PCP的残留量。试纸条检出限为10 ng/mL,检测时间为5 min。该方法检测所需试剂已预先包被在试纸条上,操作简单、重复性好、成本低廉,可用于五氯酚的现场快速检测。     

2,4-二硝基酚分光光度法测定氯氮卓

在水溶液中 ,氯氮卓与 2 ,4 二硝基酚发生荷移反应 ,生成稳定的 1∶1的配合物 .最大吸收波长为 44 4nm ,表观摩尔吸光系数为ε =1.48× 10 3L/ (mol·cm) ,线性范围 3～ 96 μg/mL ,回收率为 99.95 %～ 99.97% ,相对标准偏差为 0 .5 5 %     

掺杂碳纳米管对五氯酚吸附作用的理论研究

为了寻找检测高毒性、持久性有机污染物五氯酚(PCP)的新型材料,应用密度泛函理论研究了(8,0)和(5,5)单壁碳纳米管(SWCNT)以及相应的Si、B和N掺杂的SWCNT对PCP分子的吸附性能.计算结果表明,(8,0)和(5,5)SWCNT与PCP分子之间为物理吸附;Si原子掺杂(8,0)和(5,5)SWCNT,引起了碳纳米管掺杂部位六元环的畸变,增强了SWCNT的反应活性,掺杂后的SWCNT对PCP分子形成化学吸附,其几何结构和电子性质发生了显著变化;B和N原子掺杂的SWCNT对PCP分子的吸附没有明显增强.Si原子掺杂的SWCNT最有潜力用于检测PCP分子.     

对氯酚在碳纳米管修饰玻碳电极上的电化学行为研究

研究了对氯酚在多壁碳纳米管修饰玻碳电极（MWNTs/GC）上的电化学行为。MWNTs/GC电极对对氯酚具有良好的电催化作用,相比玻碳电极对氯酚的氧化峰电位负移76 mV,峰电流达到玻碳电极上的8倍。通过线性扫描伏安法研究了富集时间、溶液pH和扫描速率对对氯酚氧化的影响。并采用计时电流法研究了氧化峰电流与对氯酚的浓度关系,结果显示峰电流与对氯酚的浓度在2.0×10^-7-2.0×10^-4mol/L范围内呈良好线性关系,检出限为8.8×10-8mol/L（S/N=3）。放置7 d后,对氯酚在碳纳米管上的峰电流仍能达到最初电流的96.2%,表明电极的稳定性较好。     

Polychlorinated biphenyls,dibenzo-p-dioxins and dibenzofurans in soil samples from airport areas of Croatia

Levels and patterns of polychlorinated biphenyls (PCBs) were studied in surface soil samples collected in the coastal part of Croatia within and surrounding four different airports and in the vicinity of two partially devastated electrical transformer stations. The compounds accumulated from air-dried soil samples by multiple ultrasonic extraction with an n-hexane?:?acetone 1?:?1 mixture were analysed by capillary gas chromatography with electron capture and ion-trap detection. PCBs were quantified against a standard Aroclor 1242/Aroclor 1260 mixture and a standard mixture of 17 individual PCB congeners (IUPAC No.: 28, 52, 60, 74, 101, 105, 114, 118, 123, 138, 153, 156, 157, 167, 170, 180, and 189). The mass fractions of total PCBs in 18 soil samples collected within the airport premises ranged from 3 to 41?327?µg/kg dry weight (dw) (median: 533?µg/kg?dw), and those in 21 samples collected at a distance ranging from several metres to 5?km away from the airport fence, from <1 to 39?µg/kg?dw (median: 5?µg/kg?dw). The highest PCB levels were determined in soils along the airport aprons where the aircrafts were serviced and refuelled. The PCB pattern was very similar to technical Aroclor 1260 in all airport soils. The PCB pattern in 22 soils collected in the vicinity of electrical transformer stations was dominated by congeners contained in Aroclor 1242. These soils contained 7 to >400?µg/kg?dw of total PCBs. One highly PCB-contaminated airport soil sample was analysed for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). With an international toxic equivalent (I-TEQ) of 9.7?ng/kg?dw, the airport soil contamination was within values typical for urban and rural areas, and the congener patterns gave no clear indication for PCBs as the only source of PCDDs/PCDFs.     

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     

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。     

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.     

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.     

Determination of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in the Emission from Urban Incinerators

Summary An analytical procedure has been developed for analysis of emissions (ashes, fly ash, fumes and vapours) of urban waste incinerators in terms of their content of the most toxic chlorinated compounds such as polychlorinated dibenzodioxins (PCDD) and polychlorinated dibenzofurans (PCDF). It consists of a selective extraction, a careful clean-up with a silica gel and an alumina column, and gas Chromatographic analysis on high-resolution columns to separate individual constituents of the various classes and detect them with an E. C. detector. Peak identifications were made by comparison with the retention times of reference mixtures and were confirmed by GC-mass spectrometric analysis. It has been found that all emissions contain PCDDs and PCDFs with the more highly chlorinated species predominating. The highest concentration is found in the fly ash, in the range of about 1 ppm total PCDD, and 0.5 ppm total PCDF. It is shown that the formation of these compounds is due to thermal synthesis in the incineration process from precursors in the waste (phenols and chlorinated species).

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Bestimmung poly chlorierter Dibenzo-p-Dioxine und Dibenzofurane in den Emissionen städtischer Müllverbrennungsanlagen

Zusammenfassung Eine Methode zur Analyse von Emissionen städtischer Müllverbrennungsanlagen (Asche, Flugasche, Dämpfe und Abgase) wurde im Hinblick auf deren Gehalt an hochtoxischen chlorierten Verbindungen, wie PCDD (polychloriertes Dibenzodioxin) und PCDF (polychloriertes Dibenzofuran) entwickelt. Die Methode beruht auf einer selektiven Extraktion, einem Reinigungsschritt mit Hilfe einer Silicagel- und einer Aluminiumoxidsäule und letztlich einer gaschromatographischen Analyse. Die GC-Trennung erfolgte mit Hochleistungssäulen, um eine Trennung der zu analysierenden Komponenten für die Erfassung mit einem E.-C.-Detektor zu ermöglichen. Die Identifizierung der Peaks wurde durch Vergleich der Retentionszeiten von Referenzproben durchgeführt und durch GC-MS-Analyse bestätigt. In allen Emissionen wurden PCDDs und PCDFs bei Anreicherung der höher chlorierten Spezies gefunden. Höhere Konzentrationen traten in der Flugaschenprobe mit Gehalten von etwa 1 ppm Gesamt-PCDD und 0,5 ppm Gesamt-PCDF auf. Die Bildung dieser Verbindungen wird auf eine Synthese bei der thermischen Reaktion unter den Prekursoren beim Verbrennungsprozeß (u. a. Phenole und chlorierte Verbindungen) zurückgeführt.

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Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980.     

“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。     

Automated sample preparation-fractionation for the measurement of dioxins and related compounds in biological matrices: a review

This article reviews some of the recent developments in the extraction and clean-up areas of biological samples dedicated to dioxin and related compound analysis. A brief introduction on the major dioxin contamination events, which have occurred in the food chain, is given to illustrate the need of fast high throughput methods in case of crises. The emphasis of this paper is the method development based upon reliable instrumental extraction techniques for rapid sample processing and automation such as; supercritical fluid extraction (SFE), microwave-assisted extraction (MAE), pressurized liquid extraction (PLE) and, solid-phase extraction (SPE). The PLE and SPE are also discussed in conjunction with the use of a multi-column automated clean-up system that can accommodate up to 5 g of extracted lipids. The fractionation in sub-groups of analytes during the clean-up process allows the isolation of various types of toxicants from a single sample and illustrates the versatility of the system. An integrated extraction and clean-up instrument is finally presented in terms of feasibility and attainable sample turnover for the parallel processing of liquid and solid biological samples.     

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...     

Nonlinear Dependence of Bioconcentration Factors on n-Octanol-Water Partition Coefficients of Chlorinated Dibenzofurans and Dibenzo-p-Dioxins

Abstract

A nonlinear thermodynamic model is applied to the prediction of both the bioconcentration factor (K_bw) in the guppy (Poecilia reticulata) and the n-octanol-water partition coefficient (K_ow) of chlorinated dibenzofurans and dibenzo-p-dioxins. To this end molar liquid volumes, heats of vaporization and empirically fitted parameters of the pertinent solute and solvents are used. Calculated log K_bw and log K_ow values are obtained with correlation coefficients (r = 0.85 and 0.992) and mean deviations (< dev > = 0.19 and 0.17), which compare favourably with experimental data.

In addition the model enables an explanation of the well-known nonlinear log-log relationship between the two properties for compounds with high K_ow values on the basis of differences between the properties of biotic lipid and n-octanol. It is suggested that the breakdown of the linear relationship is caused by entropic effects related to the number of chlorine atoms in the solute molecules and to the structures of the lipid and n-octanol.