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。     

菠菜中噻虫嗪的残留检测与消解动态

采用高效液相色谱分析技术测定了噻虫嗪在菠菜中的残留动态和最终残留.噻虫嗪的最低检出量为1 ng,最低检出质量分数为0.002 mg/kg.在菠菜中的平均回收率为90.5%～101.4%,相对标准偏差0.75%～1.21%.噻虫嗪在土壤和菠菜中的半衰期分别为2.3 d.按180 g/hm2剂量施药3 d后,菠菜中最高残留量为0.55 mg/kg.     

噻霉酮在黄瓜和土壤中的残留分析方法

研究并建立了噻霉酮在黄瓜和土壤巾的残留分析方法.黄瓜和土壤样品分别用丙酮和二氯甲烷提取,固相萃取(SPE)净化,液相色谱(LC)测定.噻霉酮的最小检测量为1.0×10-9g,黄瓜和土壤中的最低检出质量分数均为0.01 mg/kg.在0.5～5.0 mg/kg的添加质量分数下,土壤中噻霉酮的平均添加回收率为85.9%～97.2%,变异系数为2.2%～3.8%;黄瓜中的平均添加回收率为89.2%～97.6%,变异系数为1.5%～2.4%.     

土壤中噻虫嗪和氯虫苯甲酰胺的残留分析方法

[目的]建立同时测定土壤中噻虫嗪和氯虫苯甲酰胺的多残留分析方法。[方法]样品用乙腈和二氯甲烷提取,弗罗里硅土固相萃取小柱净化,液相色谱分离,紫外254 nm分别检测噻虫嗪和氯虫苯甲酰胺,外标法定量。[结果]对土壤中的噻虫嗪、氯虫苯甲酰胺进行不同水平的添加回收率实验,方法的平均回收率为77.18%-107.27%,相对标准偏差为1.50%-8.83%。噻虫嗪和氯虫苯甲酰胺在土壤中的最低检测质量分数为0.01 mg/kg。[结论]该方法的灵敏度、准确度、精密度符合农药残留分析的要求,适合大批量样品的检测。     

超高效液相色谱-串联质谱法检测韭菜中噻虫嗪及其代谢物噻虫胺

[目的]建立同时测定韭菜中噻虫嗪及其代谢物噻虫胺的多残留分析方法。[方法]样品用乙腈提取,石墨化炭黑固相萃取小柱净化,超高效液相色谱分离,三重四级杆质谱检测,基质匹配标准溶液的外标法定量。[结果]对韭菜中的噻虫嗪、噻虫胺进行0.01~0.2 mg/kg的添加回收率试验,噻虫嗪在韭菜中的平均回收率为73.7%~98.6%,相对标准偏差2.9%~4.5%;噻虫胺在韭菜中的平均回收率72.4%~80.6%,相对标准偏差为2.1%~7.1%。噻虫嗪和噻虫胺在韭菜中的最小检出质量分数均为0.01 mg/kg。[结论]方法的灵敏度、准确度、精密度符合农药残留分析的要求,适合大批量韭菜样品的检测。     

噻虫嗪及其代谢物噻虫胺在甘蓝和土壤中的残留动态行为

[目的]为研究噻虫嗪及代谢物噻虫胺在甘蓝和土壤中的残留动态,评价噻虫嗪在甘蓝上的安全使用。[方法]采用乙腈提取农药有效成分,N-丙基乙二胺吸附剂(PSA)和石墨化碳黑(GCB)吸附净化,建立超高效液相色谱串联质谱(UPLC-MS/MS)检测方法,分析噻虫嗪、噻虫胺在甘蓝和土壤中的消解规律及残留水平。[结果]甘蓝和土壤样本中噻虫嗪及噻虫胺最低检测质量分数为0.01 mg/kg,平均回收率为81.9%～105.2%,相对标准偏差在1.5%～12.9%范围内。噻虫嗪在甘蓝和土壤中的消解半衰期分别为10.5～21.0、16.5～31.5 d;噻虫胺在甘蓝上的半衰期为15.4～21.0 d,土壤中噻虫胺的检测量均<0.02 mg/kg。[结论]该方法有足够的灵敏度、准确度和回收率等优点,适合用于甘蓝和土壤中噻虫嗪、噻虫胺的检测分析。残留分析结果表明,使用1%噻虫嗪颗粒剂的最高推荐用药量(450 g a.i./hm2)来防治甘蓝害虫,在收获期采收甘蓝安全。     

腈菌唑在黄瓜和土壤中的残留动态

建立了用高效气相色谱法测定黄瓜和土壤中腈菌唑农药残留量的方法.并研究了其在黄瓜和土壤中的消解动态和最终残留.样品用乙腈提取,过Florisil柱净化,ECD检测器检测,外标法定量.添加回收率为84.0%～106.4%,变异系数为2.2%～8.6%,该方法的最小检出量为1×10-11g,在黄瓜和土壤中的最低检出质量分数为0.010 mg/kg.残留动态试验结果表明,施药质量浓度为推荐剂量的2倍时(有效成分60g/hm2),腈菌唑在黄瓜中的半衰期为2.5～2.7d,在土壤中为14.1～14.3d.在有效成分60g/hm2的剂量下,施药5～6次,施药后第5d黄瓜中腈菌唑残留量低于0.20mg/kg.     

超高效液相色谱-质谱串联法测定双孢菇中噻虫嗪及其代谢物噻虫胺残留量

建立改进的QuEChERS提取净化方法和超高效液相色谱-串联质谱法测定双孢菇中噻虫嗪及其代谢物噻虫胺残留。样品经乙腈提取后,采用MgSO_4、PSA和C_(18)吸附净化,UPLC-MS/MS检测。研究结果表明,噻虫嗪和噻虫胺质量浓度为0.005～0.5 mg/L,方法呈良好的线性关系,相关系数大于0.995。方法的检出限为0.1 ng,定量限为0.005 mg/kg。在添加质量分数为0.005、0.01、0.5mg/kg时,方法的平均回收率为85%～112%,相对标准偏差为0.5%～7.1%。该方法准确可靠,灵敏度和准确度均达到了农药残留检测的要求。     

番茄中噻虫嗪残留量的高效液相色谱法测定

建立了测定番茄中噻虫嗪残留量的反相高效液相色谱方法。样品经甲醇提取,二氯甲烷萃取净化,残留中的噻虫嗪用二极管阵列(PDA)检测器在250nm处测定。在0.05～1.0mg/kg添加水平,回收率为83.4%～92.1%,相对标准偏差为2.06%～2.94%,其检出限为0.05mg/kg。     

高效液相色谱法测定蔬菜和土壤中氯虫苯甲酰胺甲氧虫酰肼的残留

建立了同时测定蔬菜(黄瓜、青菜、豇豆、卷心菜、番茄)、土壤中氯虫苯甲酰胺和甲氧虫酰肼农药残留的高效液相色谱法。蔬菜以乙腈高速匀浆提取,过NH2小柱净化,再用甲醇定容。而土壤样品较干净,经乙腈振荡提取1h,浓缩后定容过膜即可。采用甲醇–乙腈–水为流动相,利用C18柱和紫外检测器(检测波长:230nm)对待测组分进行了分离和测定。实验证明,添加浓度在0.05mg/kg、0.4mg/kg和1mg/kg时,蔬菜和土壤中氯虫苯甲酰胺和甲氧虫酰肼平均添加回收率在87.6%～114.4%之间,相对标准偏差(RSD)<10%,氯虫苯甲酰胺和甲氧虫酰肼在样品中的最低检出浓度为0.05mg/kg,最小检出量为1ng。     

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.