高效液相色谱法测定萝卜中定虫隆残留量

建立了快速测定萝卜中定虫隆残留方法。样品经乙腈提取,用高效液相色谱仪进行测定。实验结果表明,方法的最低检出量为1×10-9g,最低检出质量分数为0.02mg/kg,在0.1、0.5、1.0mg/kg三种添加水平下,添加回收率范围为85.16%～95.29%,变异系数范围为3.00%～7.53%。该分析方法快速、准确、灵敏,重现性好,适用于萝卜中定虫隆残留量的检测。     

高效液相色谱法同时测定甘蔗及土壤中莠灭净与敌草隆的残留

建立了用高效液相色谱法同时测定甘蔗及土壤中莠灭净与敌草隆的残留分析方法.样品经甲醇提取,二氯甲烷萃取和中性氧化铝柱层析净化,HPLC法测定,方法最小检出量莠灭净为1.2×10-9g,敌草隆为1.5×10-9g.莠灭净在土壤和甘蔗中的最低检出质量分数分别为0.015、0.02 mg/kg,方法添加回收率分别为82.12%～90.97%、85.89%～92.26%,相对标准偏差分别为1.70%～5.73%、0.40%～5.78%;敌草隆在土壤和甘蔗中的最低检出质量分数分别为0.01、0.02 mg/kg,方法添加回收率分别为80.93%～82.19%、81.81%～87.81%,相对标准偏差分别为2.34%～8.60%,0.35%～6.20%.     

氟草烟在稻田水及土壤中残留分析方法

通过衍生化反应和气相色谱检测来测定稻田水、土壤样品中氟草烟的残留.氟草烟的最小检出量为2.0×10-12g,最低检出质量分数稻田水中为0.001 mg/kg、土壤中为0.002 mg/L.稻田水中氟草烟的平均添加回收率为96.16%～103.20%,变异系数为2.34%～6.97%;土壤中的平均添加回收率为81.35%～94.27%,变异系数为4.26%～6.52%.     

噻虫嗪在土壤中的残留分析方法研究

建立了噻虫嗪在土壤中的残留分析方法。样品用甲醇提取,二氯甲烷萃取,液相色谱（SPD）测定。噻虫嗪的最低检出量：4×10-10g;最低检出浓度为0.01mg/kg。土壤添加回收率为86.3%～91.2%,相对标准偏差为2.8%～4.5%。结果表明,该方法符合农残分析要求。     

GC法测定苹果中丙森锌的残留

报道了用GC法来测定苹果中丙森锌的残留。在选定的试验条件下,丙森锌的最低检出量为1.0×10-10g。当添加浓度为0.05～5mg/kg时,丙森锌在苹果中的回收率为87.5%～99.9%,变异系数为4.23%～8.15%。     

多菌灵在柑桔及土壤中的HPLC残留分析方法

用稀盐酸和甲醇混合溶液提取柑桔和土壤样品中的多菌灵,并采用液相色谱法测定了样品中残留的多菌灵。检测线性范围为1~2000 ng,相关系数r = 0.9996,最低检出量1.0×10-10 g,最低检测浓度:土壤0.025 mg/kg;果肉、果皮和全果0.010 mg/kg。多菌灵在不同样品中的添加回收率在80.1%~105.4%之间,满足农药残留分析要求。     

甘蓝中吡蚜酮残留量的高效液相色谱分析

建立了吡蚜酮在甘蓝中的残留分析方法.样品经乙腈和二氯甲烷提取、柱层析净化后,进行高效液相色谱检测.最小检出量为1.0×10-10g,最低检出质量分数为0.005mg/kg,样品平均添加回收率为90.62%～95.09%.该方法简便快捷,符合农药残留检测要求.     

双氧威在土壤及水中残留分析方法

建立了双氧威在土壤及水中的残留分析方法.土壤和水样品分别以丙酮和乙腈提取,高效液相色谱-DAD检测器检测.双氧威的最小检出量为2.0×10-11 g,土壤中的最低检出质量分数为0.03 mg/kg,水中为0.03 mg/L.土壤中双氧威的平均添加回收率为83.5%～100.8%,变异系数为3.2%～6.8%;水中的平均添加回收率为96.2%～100.8%,变异系数为0.7%～2.3%.该方法的准确度、精确度及灵敏度均达到农药残留分析的要求.     

吡蚜酮在水稻植株、大米和土壤中残留量的测定方法研究

建立了吡蚜酮在水稻植株、大米和土壤中残留量的液相色谱定量检测方法。样品经乙腈提取,过SPE C18小柱净化,高效液相色谱(UV)测定,吡蚜酮的最小检测量为5×10-10 g,在植株、大米和土壤中最低检出浓度均为0.05 mg/kg。水稻植株中吡蚜酮的添加回收率为88.76%～103.9%,变异系数为7.63%～9.29%;大米中吡蚜酮的添加回收率为90.49%～91.38%,变异系数为3.43%～4.62%;土壤中吡蚜酮的添加回收率为90.24%～91.40%,变异系数为3.32%～5.15%。方法的线性范围在0.05～10 mg/L,方程y=4533.7 x+15302,相关系数0.9984。该方法的准确度和灵敏度均符合农药残留的分析要求。     

硝磺草酮在玉米上的残留研究

研究了硝磺草酮在玉米植株、籽粒和土壤中的残留分析方法及残留动态。结果表明,硝磺草酮最小检出量为0.3ng,在植株、籽粒及土壤中的最低检测浓度分别为0.02mg/kg、0.01mg/kg和0.01mg/kg。硝磺草酮在植株中添加回收率为80.94%～89.0%,相对标准偏差为3.66%～12.54%;籽粒中添加回收率为78.11%～87.15%,相对标准偏差为3.95%～11.54%;土壤中添加回收率为81.27%～95.38%,相对标准偏差为4.25%～6.28%。植株中半衰期为5.6～6.8d,土壤中半衰期为10.4～10.8d。     

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。