石墨炉原子吸收法测定空气中铅和镉

本文建立了采用微孔滤膜采集空气中铅和镉,自动石墨消解仪对滤膜样品进行前处理,石墨炉原子吸收法进行测定的方法。本实验优化了消解液的组合,使滤膜样品消解更完全,当采样体积为300L,铅、镉的最低检出质量浓度分别为0.0001、0.00001mg·m~(-3),加标回收率在92.1%～103.4%之间,6次测定的相对标准偏差均小于4%。该方法具有前处理简单、污染小、检出限低、精密度和准确度较好等优点,适用于大批量环境空气中痕量铅和镉的分析。     

微波消解-原子荧光法测定颗粒物中砷、硒、铋、锑的不确定度评定

大气颗粒物的成分复杂，性状多样，容易受到各种环境因素的影响，通过分析大气颗粒物中重金属含量及变化，对评价城市环境空气污染状况及污染物的来源具有重要的意义。采用滤膜收集环境空气中的总悬浮颗粒物，利用微波消解-原子荧光法分析环境空气样品中As、Se、Bi、Sb元素，对其不确定度进行了评估，主要包括标准溶液配置、标准曲线拟合、重复测定样品、样品采集过程中4个不确定度分析，为类似的不确定度评定提供了参考依据。     

原子荧光光谱法测定环境空气中的锡及其化合物

用微孔滤膜采集环境空气中锡及其化合物,采集的样品经消解后用原子荧光光谱法测定其中锡的含量,对消化液和还原剂的选择进行了探讨。锡浓度在0.0~50.0μg/L范围内与荧光强度呈良好的线性关系,相关系数R=0.9997,加标回收率为91.8%~97.2%,方法的检出限为0.15μg/L,测定结果的相对标准偏差为3.24%~4.75%(n=6)。该方法适用于环境空气中锡及其化合物浓度的测定。     

石墨炉原子吸收法测定空气中钴

建立了石墨炉原子吸收法测定空气中钴的方法。采用微孔滤膜采集,微波消解样品,以硝酸镁溶液作基体改进剂。本方法前处理操作过程简单、酸用量少,方法的最低检出浓度为0.002μg/m~3(以采集环境空气量为1200 L,定容体积为50 mL计),样品的加标回收率为92.7%~103%。本方法测定结果准确度高,精密度好,检出限低,可作为一种检测方法用于空气中钴的测定。     

微波消解—电感耦合等离子体质谱法同时测定交通环境下大气颗粒物中的铅、镉、锰、锌

探索并建立微波消解滤膜样品,电感耦合等离子体质谱法同时测定交通环境下大气颗粒物中的铅、镉、锰、锌的方法。实验表明:标准滤膜样品中各元素多次测定结果与标准值一致,相对标准偏差RSD均小于5%,滤膜实际样品加标回收率为95.2%~104%。该方法检出限低,准确性和精密度良好,简便、快速、灵敏,是一种可靠的分析交通环境下大气颗粒物中铅、镉、锰、锌的新方法。     

火焰原子吸收测定阿胶中铜的含量

采用微波消解-火焰原子吸收光谱法测定阿胶中铜的含量。微波消解阿胶样品具有方便、快捷、污染少特点,并且可以完全消解样品;方法考查了8种牌号的阿胶产品,方法检出限为0.006μg/mL,方法的加标回收率97.8%~108.0%,相对标准偏差小于2%,结果令人满意。     

微波消解-原子吸收分光光度法测定土壤中铜、锌、铅、镍、铬的研究及应用

建立了微波消解-原子吸收分光光度法测定土壤中痕量铜、锌、铅、镍、铬的方法。优化微波消解条件,通过硝酸-盐酸-氢氟酸-高氯酸体系消解液对土壤样品进行消解,样品经消解浓缩后定容至5 mL,在仪器最佳的条件进行测定。结果表明:铜、锌、铅、镍、铬5种金属元素均呈现良好的线性关系,相关系数范围为0.999 3～0.999 9,检出限范围分别为0.5,1.0,6.0,1.2,0.7 mg/kg,测定下限分别为2.0,4.0,24.0,4.8,2.8 mg/kg,平均回收率范围为86.8%～109%,相对偏差范围在2.67%～5.78%。该方法稳定性好,操作简单,灵敏度高,满足土壤中铜、锌、铅、镍、铬测定。     

石墨消解火焰原子吸收法测定茶叶中微量元素

本文研究了石墨消解仪与火焰原子吸收光谱仪(FAAS)联用测定茶叶中铜、锌、铁、锰4种微量元素的方法。经过对消解液和样品消解量的优化,确定了一个最适合茶叶样品消解的前处理方法。各元素的检出限分别为Cu0.50,Zn0.12,Fe0.25,Mn0.20mg·kg-1。回收率为94.8%~101%,精密度为0.5%~1.1%。该方法准确、快速、高效,是进行茶叶中微量元素测定的实用方法。     

微波消解-火焰原子吸收法测定土壤中铜锌铅镍锰

讨论了用原子吸收光度法测定土壤中铜、锌、铅、镍和锰。通过硝酸-氢氟酸-高氯酸以及硝酸-盐酸-过氧化氢体系消解液对土壤样品消解,选择出微波最佳消解条件。对硝酸-氢氟酸-高氯酸体系消解液和硝酸-盐酸-过氧化氢体系消解液进行消解对比试验,发现前者将土壤样品中的铜、镍和锰完全消解,后者能将样品中的锌和铅消解完全。微波消解土壤和传统电热板消解在测定前都需将消解液中剩余的酸赶尽,但与传统电热板消解相比,微波消解操作简便快速,可提高工作效率。     

土壤中重金属消解方法的对比研究

利用标准样品对比研究了3种不同消解方法测定土壤中重金属元素的差异。将(1)电热板消解(2)微波消解(3)全自动消解仪快速消解预处理方法进行分析比较,分析多种消解方法的优点和缺点,推荐实用、准确、高效、方便快捷的消解预处理方法。并对多种消解样品分别测定铜、锌、铅、镉、铬、镍重金属元素含量验证推荐消解方法的预处理效率。结果表明,电热板加热消解将土壤样品彻底消解,但消解时间略长,消解过程敞开系统,对操作人员造成危害;微波消解密封消解避免了一些易挥发组分的损失,并且外源性污染少;快速消解方法速度较快,但消解不完全。     

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.     

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。     

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.