基质固相分散萃取-超高效液相色谱-串联质谱法快速测定蔬菜中的农药多残留

[目的]建立蔬菜中17种农药多残留的超高效液相色谱一串联质谱(JPLC-MS-MS)检测方法。[方法]样品采用基质固相分散萃取技术进行提取和净化,超高效液相色谱分离、二级质谱检测器测定。[结果]17种农药在0.005~0.5 mg/L范围内线性关系良好、相关系数r≥0.999 5,检出限0.001~0.004 mg/L;添加水平在0.025~0.25 mg/kg范围内,平均添加回收率为73.44%~101.58%、相对标准偏差为0.73%~11.09%。[结论]该方法快速、准确、简便、经济、高效、安全,可用于蔬菜样品中农药多残留确证检测。     

超高效液相色谱-串联质谱法测定杨梅中噻嗪酮残留量

[目的]建立超高效液相色谱-串联质谱法测定杨梅中噻嗪酮残留量的方法。[方法]杨梅样品经乙腈提取,弗罗里硅土柱净化,超高效液相色谱-串联质谱检测。[结果]噻嗪酮在0.5~500μg/L范围内线性关系良好,相关系数为0.9952,在0.01~2.0 mg/kg添加水平下,噻嗪酮在杨梅中的平均回收率为88%~92%,相对标准偏差为2.43%~3.88%,噻嗪酮在杨梅中的定量下限为0.01 mg/kg。[结论]该方法简便、快速、准确、灵敏度高,可用于杨梅中噻嗪酮的残留检测。     

气相色谱-质谱法快速测定蔬菜中甲拌磷残留量

建立了采用气相色谱-质谱联用技术快速、准确测定蔬菜中甲拌磷残留量的方法,通过液-液提取的方式对蔬菜样品进行前处理,提取后使用气质联用仪进行分析。该方法选择性好,灵敏度高,甲拌磷检测线性范围为0.01~0.2mg·L~(-1),检出限为0.005mg·kg-1,加标回收率在83.5%~91.3%之间,可以作为蔬菜中甲拌磷残留量的检测和确证方法。     

大米中环已烯酮类除草剂残留量的测定

建立了大米中环己烯酮类除草剂残留量同时测定的液相色谱-质谱/质谱法。试样中残留的环己烯酮类除草剂用酸性乙腈高速匀浆提取,提取液经N-丙基乙二胺（PSA）、十八烷基硅烷（ODS）和石墨化炭黑净化,用液相色谱-质谱／质谱仪检测和确证,外标法定量。环己烯酮类除草剂的浓度在0．0025～0．1000μg·mL^-1范围内时,线性关系良好,8种环己烯酮类除草剂的相关系数为0．9947～0．9992。在0．005～0．050mg·kg^-1浓度范围内,样品平均加标回收率在73．2％～107．0％之间,相对标准偏差为5．14％～10．15％。8种环己烯酮类除草剂的最低检出限均为0．005mg·kg^-1。     

高效液相色谱法测定化妆品中烟酰胺的含量

建立了一种测定化妆品中烟酰胺的高效液相色谱方法。试验以质量分数0.1%甲酸水溶液-甲醇(体积比95∶5)为流动相,用C18色谱柱分离,流速为1.0mL/min,检测波长260nm,检测化妆品中的烟酰胺。结果显示烟酰胺线性范围为0.5~20mg/L,化妆品中定性检出限为0.50mg/kg,平均回收率为91.3%~109.4%。此方法样品处理简单,分析准确可靠,适用于对各类化妆水和护肤霜中烟酰胺的检测。同时对于阳性样品,建立了液相色谱-串联质谱的确证方法。     

大米中环己烯酮类除草剂残留量的测定

建立了大米中环己烯酮类除草剂残留量同时测定的液相色谱-质谱/质谱法。试样中残留的环己烯酮类除草剂用酸性乙腈高速匀浆提取,提取液经N-丙基乙二胺(PSA)、十八烷基硅烷(ODS)和石墨化炭黑净化,用液相色谱-质谱/质谱仪检测和确证,外标法定量。环己烯酮类除草剂的浓度在0.0025～0.1000μg.mL-1范围内时,线性关系良好,8种环己烯酮类除草剂的相关系数为0.9947～0.9992。在0.005～0.050mg.kg-1浓度范围内,样品平均加标回收率在73.2%～107.0%之间,相对标准偏差为5.14%～10.15%。8种环己烯酮类除草剂的最低检出限均为0.005mg.kg-1。     

超高效液相色谱-串联质谱法测定茶叶中氯噻啉的残留量

[目的]建立一种超高效液相色谱-串联质谱测定茶叶中氯噻啉残留量的方法。[方法]样品用乙腈匀质提取,经GC-e/NH2柱去除杂质,经C18液相柱分离后,用电喷雾离子化-串联质谱测定。[结果]在12.5~100.0滋g/L质量浓度范围内,氯噻啉工作曲线相关系数(R2)为0.994 5,仪器最小检出量为5.98×10-13 g。在0.025、0.25、2.50 mg/kg添加水平下,茶叶中氯噻啉回收率在94.66%~96.30%之间,相对标准偏差小于8.0%,方法最低检出限为0.99×10-3mg/kg。采用该方法对实际样品进行测定,均未检出氯噻啉残留。[结论]方法准确、快速、稳定,能够满足实际残留检测的需要。     

液相色谱-串联质谱法检测黄瓜中氯吡脲的残留量

介绍了利用液相色谱-串联质谱快速、准确测定黄瓜中氯吡脲残留量的方法。样品用乙腈提取,Carb/NH2固相萃取小柱净化,多反应监测技术检测。方法的检出限为0.002 mg/kg,线性范围为0.001~0.100 mg/L,相关系数为0.9997;在0.01~0.20 mg/kg的添加浓度下,氟吡脲的加标回收率为95.0%~111.0%,相对标准偏差(RSD)为2.99%~4.78%。     

超高效液相色谱串联质谱法测定鸡肉中噻节因残留

建立鸡肉中噻节因的超高效液相色谱串联质谱(UPLC-MS/MS)残留测定方法。鸡肉样品选用乙腈提取,采用UPLC-MS/MS多反应模式(MRM)进行分析测定。噻节因添加质量在0.2~10μg范围内,方法平均回收率为87.6%~101.6%,相对标准偏差为2.44%~5.90%。方法的最小检出量为0.005 mg/L,最低检测浓度为0.01 mg/kg。该方法简单、准确,重复性较好,适用于禽蛋中噻节因的残留检测。     

超高效液相色谱质谱法测定水和鱼体中唑菌酯残留

[目的]建立用于水和鱼体中唑菌酯残留检测的超高效液相色谱-串联质谱方法。[方法]水样前处理方法利用二氯甲烷为萃取剂,鱼样前处理方法以乙腈为提取剂,通过优化色谱分离等条件,建立超高效液相色谱-串联质谱法,结合目标物标准曲线进行外标法定量分析。[结果]方法最低检出限为鱼体内1.0μg/kg,水0.05μg/L。在0.05~1.00μg/L添加水平范围内,水中平均回收率为92.0%~94.0%,相对标准偏差为1.6%~3.3%。在0.05~1.00 mg/kg添加水平范围内,鱼体中平均回收率为72.3%~105.7%,相对标准偏差为3.3%~7.4%。[结论]所建立的超高效液相色谱-串联质谱方法,可以对水和鱼体中唑菌酯农药残留实现准确定性、精确定量分析,达到农药残留分析测试要求。     

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。