免疫亲和层析净化高效液相色谱法测定澳洲坚果中黄曲霉毒素B_1

建立了一种测定澳洲坚果中黄曲霉毒素B1的免疫亲和层析净化高效液相色谱法。采用甲醇-水提取,提取液经过滤、水稀释、净化,甲醇洗脱溶解,柱后衍生液相色谱仪荧光检测器测定。实验结果表明,澳洲坚果中黄曲霉毒素B1的检出限为0.2μg/kg,在添加水平为5、10、20μg/kg的回收率实验中,平均回收率为81%~96%,相对标准偏差为0.8%~3.7%。     

婴幼儿谷类辅助食品中黄曲霉毒素B1和M1残留量的测定

建立用MycoSepTM净化柱和高效液相色谱法测定婴幼儿谷类辅助食品中黄曲霉毒素B1和M1残留量。样品经乙腈∶水(体积比84∶16)提取,提取液通过MycoSepTM226柱净化、浓缩,三氟乙酸和正己烷进行衍生化,C18色谱柱分离,荧光检测器检测,外标法定量。实验表明,黄曲霉毒素在1.25~12.5 ng/mL线性关系良好(r≥0.999),在有机燕麦粉和有机多种谷粉中分别添加1.0μg/kg和2.0μg/kg进行加标回收试验,回收率为84.6%~103.9%,相对标准偏差为1.0%~6.0%,黄曲霉毒素B1、M1最低检测限均为0.05μg/kg和0.08μg/kg。此方法不仅定量准确,精密度高且操作方便,同时也适合黄曲霉毒素G1、B2、G2、M2的测定。     

LC-MS法测定花生中黄曲霉毒素的研究

研究了液相色谱-质谱联用技术检测花生中的黄曲霉毒素.用80%甲醇溶液提取花生中的黄曲霉毒素,经免疫小柱净化,以甲醇-乙酸水为流动相,在C18柱上对黄曲霉毒素B1、B2、G1、G2进行分离,采用质谱正离子模式对黄曲霉毒素进行检测.结果表明,本方法可以同时检测花生中的黄曲霉毒素B1、B2、G1、G2,检测限分别为0.15 μg/kg、0.09 μg/kg、0.251 μg/kg、0.5 μg/kg,回收率为78%～110%,相对标准偏差为5.0%～10.3%.     

高效液相色谱-串联质谱法测定水产品中黄曲霉毒素G2、G1、B2、B1

建立了用高效液相色谱-串联质谱法（HPLC-MS/MS）测定水产品中黄曲霉毒素G2、G1、B2、B1残留量的方法。84%甲醇水溶液提取水产品中4种黄曲霉毒素,正己烷脱脂,HLB固相萃取柱净化。采用电喷雾电离,正离子扫描,选择多反应检测模式（MRM）监测,外标法定量。该法对4种黄曲霉毒素标准曲线的线性回归系数均在0.99以上,黄曲霉毒素G1、B1方法定量限为0.5μg/kg,G2、B2方法定量限为0.3μg/kg。4种黄曲霉毒素的回收率为56%～80%,相对标准偏差1.58%～14.4%。该法灵敏,结果可靠,可用于水产品中黄曲霉毒素的测定。     

UPLC法测定花生酱中黄曲霉毒素B_1、B_2、G_1、G_2

建立了免疫亲和柱净化-超高效液相色谱法测定花生酱中黄曲霉毒素B_1、B_2、G_1、G_2的方法。试样经甲醇-水(55+45)提取,振荡、离心后,下层提取液经过滤、稀释、玻璃纤维滤纸二次过滤后,通过含有黄曲霉毒素特异性抗体的免疫亲和柱,以甲醇洗脱毒素。采用超高效液相色谱仪结合荧光检测器进行分析。结果表明,方法的检出限为0.1μg/kg,定量下限为1.0μg/kg,黄曲霉毒素B_1的回收率为88%~102%;黄曲霉毒素B_1的重现性为2.5%~6.5%。该方法操作简便、准确、回收率高、重现性好,可用于花生酱中黄曲霉毒素B_1、B_2、G_1、G_2的检测。     

高效液相色谱柱后衍生法测定中药材中的黄曲霉毒素

检测普洱城区僵蚕、陈皮、桃仁、胖大海4种中药材的黄曲霉毒素,了解其污染状况。样品经70%甲醇提取、免疫亲和柱净化后,用HPLC-柱后衍生-荧光检测器进行分析测定药材中的黄曲霉毒素(G2、G1、B2、B1)含量。检测的80个样品中,共有7个样品检出黄曲霉毒素,黄曲霉毒素B1的含量最高为1.89μg/kg,黄曲霉毒素总量最高为3.57μg/kg。尽管未超出国家药典规定范围,但是普洱城区4种中药材存在一定的黄曲霉毒素污染的风险。     

乙醇水体系提取花生油中黄曲霉毒素B1的方法研究

用三氟乙酸衍生化后以高效液相法测定,对不同比例的乙醇与水对花生油中黄曲霉毒素B1的提取效率进行了研究。结果发现,以80%乙醇-水为提取液提取效果较好,在0.l～60μg/L范围内线性关系良好,其相关系数(R2)大于0.9999,方法检出限(S/N=3)为0.5μg/kg,平均回收率为83.2%;本方法的日内相对标准偏差不高于5.3%,日间相对标准偏差不高于4.6%。方法准确、灵敏,适用于花生油中黄曲霉毒素B1的测定。     

免疫亲和柱净化-HPLC法测定植物油中黄曲霉毒素

目的:建立一种免疫亲和柱净化-高效液相色谱同时测定植物油中黄曲霉毒素B_1,B_2,G_1,G_2的方法。方法:试样用甲醇水(55+45,体积比)提取,提取液经离心、过滤、稀释后,用免疫亲和柱净化,采用高效液相色谱-大体积流通池荧光检测器检测。结果:在优化条件下,黄曲霉毒素B_1,G_1的检出限分别为0.067μg/kg,黄曲霉毒素B_2,G_2的检出限分别为0.02μg/kg,回收率范围为94.0%~105.7%。结论:该方法简便快速,灵敏度高,重复性好,可满足植物油中黄曲霉毒素含量检测的需要。     

QuEChERS-超高效液相色谱-串联质谱法测定植物油中黄曲霉毒素

建立了Qu ECh ERS-超高效液相色谱-串联质谱法(UPLC-MS/MS)同时测定植物油中4种黄曲霉毒素(B1、B2、G1、G2)的方法。样品经过1%甲酸酸化的甲醇/乙腈(V(甲醇)∶V(乙腈)=85∶15)溶液提取,Qu ECh ERS(Mg SO4+C18+PSA)净化,UPLC-MS/MS多反应监测模式测定,外标法定量。4种黄曲霉毒素的浓度在0.5~50.0μg/L范围内呈良好线性关系,相关系数均大于0.99,加标回收率为84.3%~103.2%,相对标准偏差为2.9%~7.6%,方法检出限为0.2~0.3μg/kg。该方法具有简单、快速、可靠的优点,串联质谱提供的离子对扫描能够很大程度上减少基质干扰。     

中性氧化铝柱净化-UPLC-MS/MS法测定乳和乳制品中黄曲霉毒素M_1

建立了中性氧化铝固相萃取柱净化,超高效液相色谱-串联质谱法(UPLC-MS/MS)测定乳和乳制品中黄曲霉毒素M1的分析方法。样品经乙腈提取,乙酸锌辅助沉淀蛋白,中性氧化铝SPE柱净化,以乙腈和0.1%甲酸水溶液作为流动相进行梯度洗脱,以电喷雾离子源(ESI)在正离子多反应监测(MRM)模式下进行测定,外标法定量。结果表明,黄曲霉毒素M1在0.1~50μg/L浓度范围内呈良好的线性关系,相关系数(r2)大于0.99;空白样品加标回收率在70.8%~79.2%之间,相对标准偏差小于8%。方法检出限为0.02μg/kg,定量限为0.05μg/kg。该方法实用、准确、灵敏,适用于乳和乳制品中黄曲霉毒素M1的测定。     

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。