PT-GC-AFS法测定水质中甲基汞和乙基汞的适用性研究

采用吹扫捕集/气相色谱冷原子荧光光谱(PT-GC-AFS)法检测水质样品中甲基汞和乙基汞，根据测定结果分析方法的标准曲线相关系数、检出限、精密度和准确度等性能参数。实验结果表明，PT-GC-AFS法测定甲基汞和乙基汞时，甲基汞和乙基汞含量在0.0～1 000 pg范围内线性关系较好；PT-GC-AFS法测定甲基汞的检出限为0.002 ng/L,测定下限为0.008 ng/L,乙基汞的检出限为0.003 ng/L,测定下限为0.012 ng/L;PT-GC-AFS法测定水样的甲基汞和乙基汞精密度在1.3%～8.0%,满足标准方法要求的≤20%;PT-GC-AFS法的实际样品加标回收测试中，加标回收率范围为90.2%～98.0%,满足标准方法要求。PT-GC-AFS法测定甲基汞和乙基汞标准样品的总体相对误差范围为-3.7%～4.7%,表现出较高的准确度。PT-GC-AFS法测定能够满足常规水质中甲基汞和乙基汞的检测需求。     

毛细管柱气相色谱法测定水质中烷基汞的研究

采用巯基棉富集水质中的烷基汞,再用2.0 mol/L的氯化钠和1.0 mol/L的盐酸混合溶液进行解析,然后用1.0 mL甲苯萃取,最后用带有电子捕获检测器的气相色谱仪测定水质中的烷基汞。研究了气相色谱仪测定烷基汞的稳定性,确定了仪器的检出限,考察了本方法测定烷基汞的回收率和精密度。测定192.31μg/L标液三次的结果表明仪器的稳定性非常好,甲基汞和乙基汞峰面积的相对平均偏差分别为0.33%～1.11%和1.43%～3.19%。在5.0～49.50μg/L范围内,测定的工作曲线线性良好。对质量浓度最低点重复测定8次,计算出甲基汞和乙基汞的仪器检出限分别为1.04μg/L和1.15μg/L。当取样量为1 000 mL时,本方法检出限可以达到10^(-9)级(ng/L)。空白加标试验中甲基汞和乙基汞的平均回收率分别为66.70%和84.62%。对实际水样进行平行实验的平均相对偏差为0.85%,本方法的准确度和精密度良好,能满足一般水质的环境监测要求。     

毛细管柱气相色谱法测定固废浸出液中烷基汞

建立了毛细管柱气相色谱法测定固废浸出液中烷基汞的分析方法。采用硝酸/硫酸-翻转震荡法对固体废物样品进行浸提后,经疏基棉富集和盐酸氯化钠溶液洗脱,再用甲苯萃取,最后用带有电子捕获检测器的毛细管柱气相色谱对固废浸出液中烷基汞进行测定。甲基汞和乙基汞的检出限分别为8 ng/L和14 ng/L,相对标准偏差分别为2.7%～5.5%和2.0%～4.7%,平均回收率分别为81.6%～86.0%和77.5%～83.6%。该方法检出限低、准确度和精密度高,适合于固废浸出液中烷基汞的测定。     

毛细管柱气相色谱法测定市政污水中的烷基汞

采用HP-5毛细管柱气相色谱法测定水中烷基汞。测定范围为0.07~0.7mg/L,甲基汞相关系数为R=0.999,乙基汞相关系数为R=0.998。甲基汞和乙基汞的回收率在85%~95%之间。测定结果的RSD2%。     

GC-MS测定水中烷基汞的方法研究

烷基汞是汞在自然界中的一种有机物形态。广泛存在于大气环境、水环境及土壤环境中。文章主要介绍了如何使用巯基棉提取水中的烷基汞、并用GC-MS测定烷基汞。在保证测试结果准确的前提下,改进了洗脱速率和洗脱装置,本法的检出限为：甲基汞（MMC）10ng／L,乙基汞（EMC）10ng／L。     

丙基化衍生-吹扫捕集-原子荧光光谱法同时测定动物源食品中的甲基汞和乙基汞

建立了丙基化衍生-吹扫捕集-原子荧光光谱法定量测定动物源食品中甲基汞与乙基汞的方法。样品经碱溶前处理后,用四丙基硼化钠衍生试剂将甲基汞与乙基汞转化为易挥发的衍生产物,在线吹扫捕集进行富集并进一步消除基体干扰。实验结果表明,用此法检测动物源食品中甲基汞和乙基汞标准曲线线性良好,相关系数均达到0.9999,甲基汞与乙基汞的检出限分别为0.0010 ng/L和0.0015 ng/L,加标回收率为88.6%～102%。该方法具有灵敏度高、分离效果好,重现性好等优点,适用于动物源食品中甲基汞和乙基汞的检测与确证。     

高效液相-荧光法测定花胶中的有机汞

用高效液相-荧光法对花胶(20宗)中的有机汞(甲基汞和乙基汞)进行测定,并对结果进行分析与讨论;回收率分别在85.9%～90.5%,甲基汞和乙基汞的检出率达到25%～30%,超标率为5%,相关系数r=0.9994,相对标准偏差为1.62%～1.93%之间。实验表明:该法具有选择性好、检出率高、准确等优点;花胶中的有机汞检出限低,分析方法线性好,检出率高,精密度较好。     

液相色谱-原子荧光法测定水中形态汞的方法证实

本实验参照《环境监测分析方法标准制修订技术导则》HJ 168-2010对液相色谱-原子荧光法测定水中不同形态汞的方法[1]展开了方法检出限、精密度和准确度等相关证实实验。结果表明:(1)该方法中无机汞、甲基汞和乙基汞的检出限分别为0.066μg/L、0.091μg/L和0.071μg/L;(2)在低、中、高3个浓度水平下,无机汞、甲基汞和乙基汞的相对标准偏差均小于5%;(3)在低、中、高3个浓度水平下,无机汞、甲基汞和乙基汞的加标回收率较好。本实验说明,应用LC-AFS方法进行水质形态汞的分析具有一定的有效性和可行性,且适用于化学分析实验室大批量的样品处理。     

中成药中汞的原子荧光光谱法测定

方法采用硝酸-过氧化氢消解试样,以硝酸为测定介质,硼氢化钾为还原剂,用氢化物发生-原子荧光光谱法测定中成药中的汞含量.结果表明:汞含量在0～10.00ng/mL浓度范围内线性关系良好(r=0.9999);方法检出限为0.056 ng/L;相对标准偏差小于4.61%;回收率为96.6%～103.8%.     

连续流动冷原子荧光法测定水中的痕量汞

以溴化钾-溴酸钾消解样品,应用连续流冷原子荧光光谱法测定天然水体中的痕量汞。研究了还原剂氯化亚锡(SnCl_2)浓度和酸度、连续流的样品和还原剂流速、分析时间等对荧光信号的影响。结果表明,在最佳分析条件下,汞在0～10.0 ng/L范围内浓度与荧光强度线性关系良好,标准曲线线性回归方程为:IF=2.755 8c-1.018,线性相关系数为0.996 5,仪器检出限为0.18 ng/L。湖泊水样测定结果分别为4.06,7.10 ng/L。样品测定精密度<5%,加标回收率分别为105.92%和109.27%。该分析方法操作简单,灵敏度高,适于样品的批量快速分析。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。