氢化物发生-原子荧光法测定莲藕中的微量砷

样品用硝酸—高氯酸混合酸消解,研究了氢化物发生-原子荧光法测定莲藕中微量砷的实验条件。在选定条件下,该方法的检出限为0.54μg/L,RSD小于2.16%,回收率为95%～102.3%。     

氢化物原子荧光法测定化妆品中的砷

采用微波消解技术对样品进行消解,用氢化物原子荧光法测定样品。结果表明,在0~20μg/L范围内,砷含量与原子荧光强度呈良好的线性关系,相关系数为0.9997,方法检出限为0.0088μg/L,样品加标回收率在95%~105%。     

氢化物发生-原子吸收法测定食品容器等样品中锑

本文研究了用氢化物发生-原子吸收法测定食品容器等样品中的锑含量,样品用4%乙酸提取,采用氢化物发生-原子吸收法进行测定。本文实验利用添加法测定回收率,其平均回收率为95.0%~102.0%,本方法RSD小于5.3%,低检出限0.001mg·L-1。     

氢化物原子荧光法测定化妆品中的锑

采用微波消解技术对样品进行消解,用氢化物原子荧光法测定样品。对仪器参数如负高压、灯电流等进行优化实验,确定最佳实验参数。在0~20μg/L范围内,锑含量与原子荧光强度呈良好的线性关系,相关系数为0.999 2,方法检出限为0.026 6μg/L,样品加标回收率在88%~103%。     

巯基棉富集一原子荧光法测定锑矿中微量砷的研究

原子荧光法测定锑矿样品中的砷,锑的记忆效应最为严重;用巯基棉在盐酸介质中吸附As3＋,从而达到分离锑富集砷之目的。砷的回收率达到98%,变异系数3%,检出限1.2mg/L。     

顺序注射氢化物发生-原子荧光光谱法测定硅铁中的铅

采用HNO3-HF-HClO4消解样品,顺序注射氢化物发生-原子荧光法测定硅铁中的铅。该方法在选定的操作条件下,测定硅铁中铅的回收率为95.0%～106.0%,检出限为0.410 3 ng/mL,相对标准偏差为1%～5%。     

氢化物发生原子吸收法测定海藻类产品中无机砷

本文研究了用氢化物发生-原子吸收法测定海藻类产品中无机砷含量,样品用超声波-5%HCl酸进行提取,采用氢化物发生-原子吸收法进行测定。本文实验利用添加法测定回收率,其平均回收率为96.7%~101.0%,本方法 RSD小于5.7%,最低检出限0.018mg·kg-1。     

氢化物原子荧光法测定化妆品中的痕量汞

采用密闭微波消解技术对样品进行消解,用氢化物原子荧光法测定样品,改变仪器条件及所用溶液浓度,找出最佳仪器参数及各种因素对化妆品中汞测定的影响规律。本法的线性方程是If=181.248×c 0.333,加标回收率在97.8%~102.4%之间,相对平均偏差RSD为2.78%。本法具有操作简便、精密度好、灵敏度及回收率高的特点,有一定的实用意义。     

氢化物原子荧光法测定工业废水中的汞

采用氢化物原子荧光法测定工业废水中的汞,重点讨论了不同水样的预处理方法.对于基体比较简单的废水,适合采用溴化试剂处理水样;对于有机污染比较严重的工业废水,适合采用重铬酸钾-过硫酸钾处理水样.经过处理后的样品采用氢化物原子荧光法测定汞,操作步骤简单,测定结果误差较小,回收率为96％～105％.     

原子荧光法测定饮用水中汞的方法建立与应用

建立了用原子荧光法测定饮用水中汞的方法,通过对原子荧光光度计条件的设定,能够较好地测定水中的汞,其相对标准偏差RSD为1.23%～3.66%,不同浓度的加标回收率在95.7%～104.7%。     

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。