GC-ECD检测茶叶中4种拟除虫菊酯类农药残留研究

本文采用固相萃取法结合旋转蒸发技术进行样品的前处理,经气相色谱-电子捕获检测(GC-ECD)进行溴氰菊酯、氰戊菊酯、联苯菊酯、氯氰菊酯四种菊酯类农药残留的检测分析。茶叶样品过40目网筛,60℃震荡提取30min,固相萃取法进行前处理,经GC-ECD检测,基质外标法定量。结果表明:茶叶基质中,4种菊酯类农药峰面积响应值与其质量浓度在10~200μg/L范围内呈良好线性关系(R20.897)。在80、160μg/L二个添加水平下,4种拟除虫菊酯类农药的回收率在78.77%~125.78%,相对标准偏差为2.58%~5.78%。该方法简便快速、准确灵敏,适合茶叶中菊酯类农药残留的检测和安全监控。     

染整助剂中APEO的测试

采用叔丁基甲醚/硫酸钠溶液提取染整助剂中的APEO,讨论了萃取溶剂、分散介质、萃取体积、涡旋时间等对APEO提取效率的影响。结果表明,以叔丁基甲醚为萃取溶剂,150 g/L硫酸钠为破乳介质,可以很好地解决样品提取时可能产生的絮凝结块、沉淀和乳化等现象,空白加标回收率可达95%以上,RSD为6.1%,OP/NP检出限为10 mg/kg,OPEO/NPEO检出限为25 mg/kg。     

液相色谱-串联质谱法测定肉类中的β-受体激动剂

应用超快速液相色谱-串联质谱法技术,建立肉类中8种β-受体激动剂的检测方法,并对宁夏市售肉类进行分析。样品经pH=5.2的乙酸-乙酸钠缓冲溶液提取,MCX固相萃取柱净化;以甲醇-0.1%甲酸水溶液为流动相,用RP-ODS柱色谱柱分离,以电喷雾正离子模式进行质谱测定。三个加标水平下8种β-受体激动剂的平均回收率为76.2%~116.2%,相对标准偏差小于15.0%,检出限（S/N=3）为0.5μg/kg,定量限（S/N=10）为1.0μg/kg。该方法操作快速简单、重现性好,可用于肉类中8种β-受体激动剂的检测。     

固相萃取-气相色谱-串联质谱法测定艾草中除草剂的残留量

[目的]建立了一种固相萃取-气相色谱-串联质谱(GC-MS/MS)测定艾草中7种除草剂残留的方法。[方法]样品经过乙腈提取,GCB/PSA固相萃取柱净化后,采用气相色谱-串联质谱检测,使用外标法定量。[结果]在艾草基质中,7种除草剂在50～1000μg/L范围内线性关系良好,相关系数R2均大于0.99,在3个加标水平下的回收率为74.3%～104.3%,相对标准偏差为2.5%～9.3%。7种除草剂的检出限(LOD)为0.49～2.20μg/kg,定量限(LOQ)为10μg/kg。[结论]该方法能够同时测定艾草中7种除草剂残留。     

QuEChERS-超高效液相色谱-串联质谱法测定茶叶中丁醚脲的残留量

建立基于QuEChERS-超高效液相色谱-串联质谱测定茶叶中的丁醚脲的残留量的方法。样品经乙腈提取后用固相分散萃取剂净化除去杂质,以5mmol/L乙酸铵8∶2水:甲醇溶液,流动相B:5mmol/L乙酸铵甲醇溶液为流动相进行梯度洗脱,超高效液相色谱-串联质谱法正离子多反应监测模式(MRM)测定。丁醚脲在10μg/kg到200μg/kg的范围内线性良好,相关系数(R2)0.999。定量限10μg/kg为以茶叶为基质,在10、50、200μg/kg三个水平的加标回收率范围在70.4%~110.1%之间,相对标准偏差为5.0%~7.8%。该方法前处理快速简单,可用于对茶叶中丁醚脲的检测。     

HPLC-MS/MS法测定水和土壤中四氟甲醚菊酯残留量

采用HPLC-MS/MS法建立了一种测定水和土壤中四氟甲醚菊酯残留量的方法。通过直接提取水和土壤中的四氟甲醚菊酯,采用高效液相色谱-三重四级杆质谱联用仪,以甲醇-0.1%甲酸水溶液(体积比90∶10)为流动相,使用Eclipse Plus C18色谱柱和MSD检测器,对水和土壤中的四氟甲醚菊酯进行测定,外标法定量。结果表明,四氟甲醚菊酯在0.2～100.0μg/L质量浓度范围内具有良好的线性关系,线性相关系数为0.9993。当水中添加浓度为0.1μg/L和10.0μg/L时,四氟甲醚菊酯在不同水中的平均回收率为95.6%～107.8%,相对标准偏差为2.1%～9.8%;当土壤中添加浓度为1.0μg/kg和100.0μg/kg时,四氟甲醚菊酯在不同土壤中的平均回收率为88.0%～109.2%,相对标准偏差为1.9%～8.7%。说明该方法具有操作简单、灵敏度高、快速准确等特点,可用于水和土壤中四氟甲醚菊酯残留量的检测。     

离子交换固相萃取-液相色谱联用测定牛奶中的三聚氰胺

本文以混合型阳离子(MCX)固相萃取(SPE)小柱分离富集了牛奶提取液中的三聚氰胺,优化了固相萃取条件,复杂基质被有效去除,应用高效液相色谱(HPLC)法成功实现牛奶中三聚氰胺的检测,加标回收率接近90%。     

高效液相色谱串联质谱测定鸡、猪肉中万古霉素

建立了鸡肉和猪肉样品中万古霉素的高效液相色谱串联质谱检测方法。鸡肉和猪肉样品经5%三氯乙酸:乙腈(4:1)提取,阳离子交换固相萃取柱净化后,以0.1%甲酸5 mmol乙酸铵溶液和乙腈作为流动相,经C_(18)色谱柱分离后,采用多反映离子监测模式进行测定,外标法定量。结果表明,万古霉素在1.0～20.0 ng/mL范围内呈现良好的线性关系,相关系数(r~2)大于0.99,在5,25,50μg/kg加标水平下,万古霉素平均回收率60%～120%,方法检出限(LOD)为2.0μg/kg,方法定量限(LOQ)为5.0μg/kg。     

UPLC-MS/MS法测定饲料中万古霉素与去甲万古霉素

基于超高效液相色谱-串联质谱法(UPLC-MS/MS),建立了饲料中万古霉素和去甲万古霉素2种糖肽类抗生素的测定方法。样品经0.1%甲酸水-乙腈提取,MCX固相萃取柱净化,UPLC-MS/MS进行分析。方法学验证表明,万古霉素和去甲万古霉素在10～1 000 ng/mL范围内线性关系较好(R>0.999),定量限分别为50.3,54.7μg/kg;在100,200,1 000μg/kg加标水平下,平均回收率在79.3%～108.6%之间,相对标准偏差RSD在1.9%～9.8%(n=6)。该方法定量限低、精密度好,可应用于饲料中万古霉素和去甲万古霉素的定量分析。     

气相色谱质谱法测定土壤半挥发性有机物

采用索氏提取法、加压流体萃取法、干样法三种前处理方法分别对土壤半挥发性有机物进行测定和验证,得出索氏提取法的检出限分布在0.004～0.13 mg/kg,相对标准偏差分布在0.8%～11.1%,加标回收率分布在74%～108%;加压流体萃取法的检出限分布在0.002～0.07 mg/kg,相对标准偏差分布在0.4%～11.2%,加标回收率分布在74%～110%;干样法的检出限分布在0.004～0.11 mg/kg,相对标准偏差分布在0.2%～11.4%,加标回收率分布在74%～111%,均具备较高的精密度和回收率。三种方法均可适用于测定土壤半挥发性有机物。     

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。