二(噁)英类污染事件为什么会此起彼伏

2008年12月6日,爱尔兰政府宣布召回自2008年9月1日起上市的受到二噁英类污染的猪肉和猪肉制品,这场被认为是爱尔兰生猪养殖和肉类加工业灾难的食品污染事件还波及到很多国家。2008年3月,意大利政府宣布召回受到二噁英类污染的奶酪,使得年产值达5亿美元的意大利奶酪生产业受到沉重打击。 2006年2月,因饲料受到二噁英类污染,荷兰、比利时、德国三国共关闭了650多家养猪场。     

二噁(英)降解方法的研究

二噁是一类剧毒有机氯化物 ,已被联合国环境署和世界卫生组织列为持久性有机污染物和一级致癌物质 ,能够对环境和人类的健康造成重大危害。脱氯降解是降低二毒性的有效途径。本文对二的光降解、热降解、生物降解和化学降解脱氯作了详尽的评述 ,比较了各种降解方法的优劣 ,指出多相催化加氢脱氯降解方法将是今后的发展方向     

二噁(英)降解方法的研究

二噁(左口右英)是一类剧毒有机氯化物,已被联合国环境署和世界卫生组织列为持久性有机污染物和一级致癌物质,能够对环境和人类的健康造成重大危害.脱氯降解是降低二噁毒性的有效途径.本文对二噁的光降解、热降解、生物降解和化学降解脱氯作了详尽的评述,比较了各种降解方法的优劣,指出多相催化加氢脱氯降解方法将是今后的发展方向.     

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...     

2,6-二取代苯并二噁唑的研究(Ⅲ)——2,6-二苯乙烯基苯并二噁唑和它们的衍生物

通过2,6-二甲基苯并[1,2d;4,5d′]二噁唑和2,6-二甲基苯并[1,2d;5,4d′]二噁唑分别与苯甲醛和取代苯甲醛缩合备制取七种相应的2,6-二苯乙烯基苯并[1,2d;4,5d′]二噁唑和2,6-二苯乙烯基苯并(1,2d;5,4d′]二噁唑。测定了全部化合物的熔点、红外光谱、紫外光谱、荧光光谱、激光转换效率。     

BaTiO3 / (PU/UP-IPNS)复合材料的相容性、力学性能和阻尼性能研究(英)

以水热法合成的BaTiO3纤维和同步法制备的互穿聚合物网络为原料，采用原位分散聚合法获得了一系列BaTiO3/(PU／UP-IPNs)复合材料。采用傅立叶交换红外分光光度计跟踪考察了IPNs的聚合过程，用透射电镜观测了IPNs及其复合物的形貌。结果表明，IPNs中两相相畴尺寸在纳米级范围内，在此基础上，实现了BaTiO3纤维状的复合。动态力学性能的检测结果表明，相较纯IPNs，复合材料的阻尼损耗模量和阻尼损耗因子值均有所提高，且在低温区均出现了肩峰。复合物的最大损耗因子值均大于0．4，在约50℃范围内，E’值提高100MPa。力学性能检测结果表明，IPNs中的连续相是决定材料力学性能的主要因素；有机／无机组分间混溶性的降低，使BaTiO3/IPNs复合材料的抗张强度和断裂伸长率均下降。     

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.     

用T-jump/FTIR研究MnCP、NiCP和PbCP的快速热分解(英)

0IntroductionCarbohydrazideisahydrazinederivativewithwhitecrystalofstrongreducingbehaviors.Becauseithasmanycoordinationatoms(fournitrogenatomsandoneoxygenatom),carbohydrazidecan,therefore,beusedasmultidentateligand.Itscoordinationcom鄄poundiswidelyusedint…     

N，N′-二苄基-苯并咪唑四氯合铜(Ⅱ)化合物的合成、结构和性能研究(英)

A novel N，N′-dibenzyl-benzimidazolium tetrachlorocuprate(Ⅱ) complex, [C₂₁H₁₉N₂]₂[CuCl₄], was synthesized and its crystal structure was determined by X-ray diffraction. It crystallizes in monoclinic system, space group P2/c, a=1.203 9(2) nm, b=0.975 0(2) nm, c=1.878 2(6) nm, β=114.12(2)°, V=2.012 2(8) nm³. Its structure was identified by EA, IR and UV spectra and characterized by electrochemistry, thermal and magnetic property. The Cu(Ⅱ) atom of [CuCl₄]^2- has distorted tetrahedral coordination geometry. In the crystal structure, there are strong extensive C-H…Cl hydrogen bonds and π-π stacking interactions, which stabilized the crystal structure. CCDC: 221570.     

重庆市某高校学生膳食铬摄入水平的测定

为了解重庆市某高校学生膳食铬的摄入水平,随机选取调查对象120人,双份饭法采样食物,用火焰原子吸收分光光度法测定了膳食中铬的含量。结果表明,大学生膳食铬的平均摄入量男生为4.68 mg/d,女生为3.80 mg/d,分别是适宜摄入量(adequate Intake,AI)的23.4倍和19倍,也显著超过了铬的每日允许摄入量(acceptable daily Intake,ADI)1.0 mg/d。可见高校学生膳食铬摄入水平超过了推荐膳食摄入量和安全限量,但其对健康的影响有待进一步明确。     

Group separation of PCDDs,PCDFs, PACs and aliphatic compounds on an amino bonded stationary phase for HPLC

Summary A HPLC method for the clean up of PCDD and PCDF samples is presented. The method utilizes the possibility of separating compounds according to the number of double bonds by using an amino bonded stationary phase. Aliphatics as well as compounds with higher aromaticity than PCDD/PCDF are removed. In addition, the latter can be collected as one fraction. The fractionation in fast, done in one step and automated.     

Experiences on the analysis of PCDDs and PCDFs in pulp and paper industry matrices

Summary Some remarks on the analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans in pulp and paper industry matrices are presented. The way in which samples are dried and the solvent which is used for extraction can affect the results. For the separation of individual congeners, three capillary columns with different lengths and polarities have been compared. The effect of the resolution of the mass spectrometer has been tested for pulp samples.     

World-wide comparison on the quality of analytical determinations of PCDDs/PCDFs and dioxin-like PCBs in food

Interlaboratory comparsion exercises on the determination of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs) and dioxin-like polychlorinated biphenyls (PCBs) in three natural foodstuffs have been performed annually since 2000 by the Norwegian Institute of Public Health. Up to 77 laboratories from 24 countries world-wide have reported results. The data have been statistically analysed in order to assess the comparability of both the reported individual congener concentrations and the calculated toxic equivalents (TEQ). Due to the low concentrations of PCDDs/PCDFs and dioxin-like PCBs in food, the treatment of congeners reported as “not detected” and the identification of outliers, influence the estimation of the consensus values considerably. Based on the experiences from the first two rounds, an approach for calculation of the consensus values was established, resulting in a non-skewed distribution of data. The relative standard deviation of consensus TEQs was 13–32% for PCDDs/PCDFs and 11–45% for PCBs. Z-scores were calculated for PCDD/PCDF-TEQs using a target value of ±20% for the deviation. For food samples with a PCDD/PCDF contamination of more than half of the EU maximum level, 63–87% of the participants achieved Z-scores ±1, while for low contaminated foodstuffs about 60% of the participants had Z-scores of ±2. After four rounds of interlaboratory comparisons it can be concluded that there is a good comparability of the analytical data for dioxins and dioxin-like PCBs in food at higher contamination levels. However, the laboratories need to improve their performance when determining levels in food with low contamination of dioxin-like compounds, due to the increasing demand for analyses of such food items. The importance of determining dioxin-like PCBs is demonstrated by their large contribution to the total TEQ, especially in food from the marine environment.     

Optimization of a GC‐MS/MS Method for the Analysis of PCDDs and PCDFs in Human and Fish Tissue

This paper outlines the possibilities of selectivity and sensitivity enhancement in measuring PCDD/F congeners using an ion trap GC‐MS/MS. The pressure of the collision gas and the collision energy were optimized. The modified GC‐MS/MS method was applied to the determination of PCDDs and PCDFs in human and fish tissues. Limits of quantification were about 1 pg/g of fat for all seventeen 2378 PCDD/Fs tested (starting amount of fat, 2 g).     

缺碘区居民膳食结构及营养素摄入量对尿碘水平的影响

通过抽样调查,了解重庆市环境缺碘地区居民的饮食习惯,分析了膳食因素对人群尿碘水平的影响,为制订地方性碘缺乏病综合防治措施提供依据.采用24 h膳食回顾法,对重庆市两县居民的膳食摄人情况进行现况调查,比较各营养素摄入量.结果表明,两地膳食结构属于东方膳食模式,璧山县各营养素摄入量高于云阳县.结论:蛋白质、能量、维生素等缺...     

Development of a method for simultaneous analysis of PCDDs, PCDFs, PCBs, PBDEs, PCNs and PAHs in Antarctic air

The development of a unique analytical method for the determination of five classes of persistent organic pollutants (POPs) in atmospheric gas and the particle phase through gas chromatography coupled to high-resolution mass spectrometry is presented. Every step of the pre-analytical and analytical optimization process is described. Great effort was put into simplifying the traditional techniques, with reference to EPA and literature methods. Automated instruments were used for sample extraction and cleanup in order to enhance repeatability and reduce contamination risks. Unlike most common approaches, no separation of the analytes was performed before the GC analysis in order to avoid sample fractionation and to save time and materials. This allowed low instrumental and method detection limits (pg to sub-pg) to be achieved. Accuracy and precision were tested by fortifying the matrix and analysing standard reference materials (NIST SRM 1649b Urban Dust and 2585 Organic Contaminants in House Dust). The method was applied to five samples from Terra Nova Bay, Antarctica. Concentrations of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), polybrominated diphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs) are presented. Lighter compounds dominate the distribution and are mainly present in the gaseous phase. The observed pattern may be attributable to long-range transport. Results are in general agreement with literature data, where available.     

贵州省农村儿童膳食铁营养与贫血状况调查研究

为了解贵州农村儿童的膳食营养健康水平及贫血发生情况，探讨有效的改善措施，对８８６名１－１７岁农村儿童的膳食营养及健康状况进行了调查。结果表明，各年龄儿童的膳食营养水平及质量不高，膳食结构不合理，基本上“素食”，铁摄入主要以吸收利用率很低的非血红蛋白铁为主，占９５％以上，儿童慢性营养不良发生率较高，贫血发生率普遍高达２５％，且以学龄前儿童为高发人群。提出了几项旨在改善儿童营养健康状况、预防贫血发生的     

电子废物拆解区禽肉中二噁英及其类似物污染分析

为了了解某市电子废物拆解区二噁英及其类似物污染情况,于2017年9月至2017年10月期间,从电子废物拆解区内的村落居民家中,随机采集了鸡、鸭、鹅、鸽及鹌鹑各2批次成年放养家禽样本,研究其肉质中17种二噁英(PCDD/FS)及12种二噁英类多氯联苯(DL-PCBs)的污染水平。利用高分辨气相色谱/高分辨双聚焦磁式质谱联用(HRGC/HRMS)对采集的10批次家禽样本进行分析。结果发现,参照欧盟现行《2014/663/EU》行动标准及《(EU) No 1259/2011》最大限量标准,6批次样本超过了二噁英毒性当量行动标准(1. 25pg/g fat),其中3批次样本(2. 40pg/g fat、2. 56pg/g fat、1. 94pg/g fat)超过最大限量标准(1. 75pg/g fat); 2批次样本(0. 930pg/g fat、2. 14pg/g fat)超过了DL-PCBs当量行动标准限量(0. 75pg/g fat); 1批次样本(3. 33pg/g fat)超过二噁英和DL-PCBs毒性当量总量最大限量标准(3. 0pg/g fat)。证实该地区存在一定程度的二噁英和DL-PCBs污染。     

双份饭法评估广州某高校学生膳食硼摄入情况

为研究用改良姜黄素分光光度法测定双份饭食物中硼含量,以评估高校学生膳食硼摄入情况,用双份饭法收集10名学生3d的食物样品,记录饮水量;食物样品在用饱和Ca(OH)2调至碱性后灰化,然后在酸性条件下硼转化为硼酸,与姜黄素反应生成红色络合物,比色定量;饮用水中硼采用国标姜黄素分光光度法测定.然后计算出调查对象硼摄入量.结果...