共查询到20条相似文献,搜索用时 125 毫秒
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建立了毛细管气相色谱法测定染发剂中邻、间、对苯二胺含量的分析方法。样品用乙酸乙酯、超声波提取,离心除去杂质,然后采用毛细管分离,FID检测,保留时间定性,峰面积定量。苯二胺三种异构体在0.01~10 g/L浓度范围内线性关系良好,相关系数为0.999 5~0.999 6;邻苯二胺、对苯二胺、间苯二胺加标回收率分别为88.6%~97.8%,93.3%~105.0%,88.5%~99.1%,相对标准偏差为1.94%~2.05%(n=7),检出限分别为2,2.5,2 ng/mL。该方法简单、快速应用于实际样品测定,结果满意。 相似文献
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建立了气相色谱-质谱法测定鸡蛋中林可霉素的残留量的分析方法。样品经过提取、净化、衍生、富集浓缩,GC-MS方法测定,外标法定量。当样品中林可霉素添加量为0.04~0.20 mg/kg时,本方法相对标准偏差为1.3%~2.1%,回收率在85.5%~93.9%之间,方法检出限为0.005 mg/kg。 相似文献
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建立了固相萃取(SPE)-GC-MS法同时测定化妆品中的16种多环芳烃(PAHs)和17种邻苯二甲酸酯类(PAEs)的分析方法。样品经乙腈超声萃取后,经PSA/Slica玻璃柱净化,以Agilent Select PAH色谱柱分离,气相色谱-质谱法选择离子(SIM)监测测定。16种PAHs和17种PAEs在0.5~200μg/L范围内线性良好,相关系数均大于0.99;PAHs方法检出限为0.6~1.0μg/kg,方法定量限为1.9~3.3μg/kg,阴性样品3个添加水平的平均回收率为86.4%~112.2%;PAEs方法检出限为0.4~2.3μg/kg,方法定量限为1.5~7.6μg/kg,阴性样品3个添加水平的平均回收率为82.2%~114.1%;相对标准偏差均小于10%(n=6)。 相似文献
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[目的]建立棉隆及其代谢物异硫氰酸甲酯在番茄和土壤中的残留分析方法。[方法]样品经提取、净化后,分别采用DAD检测器和质谱检测器检测。[结果]添加质量分数为0.02~1 mg/kg时,棉隆在番茄和土壤中平均添加回收率分别为75.4%~95.8%和75.3%~90.3%,相对标准偏差分别为1.6%~7.5%和2.0%~6.0%。添加质量分数为0.02~1 mg/kg时,异硫氰酸甲酯在番茄和土壤中平均添加回收率分别为87.5%~91.9%和92.1%~94.7%,相对标准偏差分别为3.9%~9.2%和4.6%~6.5%。棉隆和异硫氰酸甲酯在番茄中的最低检出质量分数都为0.02 mg/kg。[结论]该方法快速简便,准确可靠。 相似文献
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采用气相色谱-电子捕获检测器(GC-ECD)测定了苯醚甲环唑在水稻植株、土壤、田水样品中的消解动态。田水样品用二氯甲烷萃取,植株、土壤样品用乙腈提取,净化后用GC-ECD进行检测。当苯醚甲环唑在水稻植株和土壤中的添加浓度为0.02~2.0 mg/kg时,其回收率为85.89%~105.33%,相对标准偏差(RSD)为1.49%~5.26%,在田水中的添加浓度为0.005~1.0 mg/kg时,其平均回收率为95.68%~102.13%,RSD为2.65%~6.82%;苯醚甲环唑的最小检出量为2.0×10-11 g,在水稻植株和土壤中的最低检测浓度为0.02 mg/kg,田水中的最低检测浓度为0.005mg/kg。消解动态试验结果显示,苯醚甲环唑在水稻植株、土壤和田水中的半衰期分别为2.75~5.68 d、4.68~18.93 d、0.81~6.31 d。 相似文献
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M. S. J. Simmonds W. M. Blaney F. Delle Monache M. Marquina Mac-Quhae G. B. Marini Bettolo 《Journal of chemical ecology》1985,11(12):1593-1599
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. 相似文献
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Cheng-Le Zhao Shane Porzio Alan Smith Haiyan Ge H. T. Davis L. E. Scriven 《Journal of Coatings Technology and Research》2006,3(2):109-115
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. 相似文献
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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. 相似文献
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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. 相似文献
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中蓝晨光化工研究院有限公司《塑料工业》编辑部 《塑料工业》2009,37(3)
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. 相似文献
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中蓝晨光化工研究院《塑料工业》编辑部 《塑料工业》2007,35(3):1-25,67
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。 相似文献