丙烯酸异辛酯装置黑色杂质分析及应对措施

在丙烯酸异辛酯生产中,反应器中黑色物质黏附问题严重影响装置的长周期运行。采集了丙烯酸异辛酯酯化反应器上的黑色物质样品,通过扫描电镜、热重分析仪、裂解-气质联用、顶空-气质联用、气质联用及能谱对其微观结构及组分进行了分析表征,探讨了黑色物质产生的原因及应对措施。     

顶空-气相色谱法/顶空-气质联用法测定纺织品中甲基异丁酮的残留量

建立了纺织品中甲基异丁酮残留量的快速检测方法。选用DB-624毛细管色谱柱,分别采用顶空-气相色谱法和顶空-气质联用法进行测定,并优化了顶空平衡温度及平衡时间等条件。结果表明,两种方法的回收率均在80%~105%之间,相对标准偏差均小于5%,顶空-气相色谱法的检出限和定量下限分别为0.03、0.1 mg/kg,顶空-气质联用法的检出限和定量下限分别为0.05、0.2 mg/kg。两种方法操作简单、快速,准确度和灵敏度高,重现性好,均适用于纺织品中甲基异丁酮残留量的日常检测。     

一种基于顶空-气质联用选择性测定干性食品包装纸中乙二醇乙醚乙酸酯的方法

<正>本发明公开了一种基于顶空-气质联用选择性测定干性食品包装纸中乙二醇乙醚乙酸酯的方法,属于包装材料理化指标检测技术领域。干性食品包装纸经140℃、30min顶空处理后,以萘为内标,采用HP-VOC色谱柱,气质联用选择离子扫描模式检     

顶空气相色谱-质谱联用法测定蜡烛中香茅油的含量

本文采用顶空进样气相色谱-质谱联用法测定蜡烛中香茅油的含量。选用硅油为母液,优化了色谱条件、顶空加热温度、平衡时间等实验条件,并进行了线性、精密度和回收率实验。方法简单、快速,定性定量准确可靠。     

顶空-气质联用法测定运动场地合成材料面层中9种挥发性苯系物

采用顶空-气质联用法测定了运动场地合成材料面层中9种挥发性苯系物。研究了顶空方式、顶空平衡温度、顶空平衡时间等条件的影响。在优化条件下,9种挥发性苯系物在线性范围内具有良好的线性关系,相关系数r为0.9956～0.9966,加标回收率为76%～98%,相对标准偏差(RSD)为2.8%～5.6%;当样品量为1 g时,方法检出限为1.2～5.8 mg/kg。利用该方法对四份样品进行检测,结果表明样品中有痕量挥发性苯系物检出。     

加压顶空气质联用法分析实验室模拟橡胶硫化烟气成分

开发一种加压顶空气质联用分析实验室模拟橡胶硫化烟气成分的方法。此方法的关键是设计了一个可放入顶空瓶中的微型模具。该模具底部为可透气的垫片,上部为可旋转的螺芯密封。样品放到该模具中,旋转螺芯加压后放到顶空瓶中,利用顶空加热装置准确控温、控时,模拟橡胶产品加压硫化的过程。硫化产生的气体可通过模具底部微孔释放到顶空瓶中,然后利用顶空气质对烟气中各成分进行分离检测。该方法设计简单,成本低,控温、控时准确,普适性强。     

静态顶空-气相色谱法测定环境空气中的甲醇

利用静态顶空-气相色谱法对环境空气中甲醇测定进行了研究。通过一系列条件实验,对顶空平衡温度,顶空平衡时间,氯化钠加入量等因素进行了优化。并对方法检出限,线性范围和加标回收率进行了测定,同时对实际样品进行了测试。结果显示:该方法检出限为0.05mg/m3,实样测试加标回收率在86%-106%,适用于环境空气中甲醇的测定。     

气相色谱法中顶空分析技术有关问题的探讨

介绍了气相色谱分析法中顶空技术的原理和特点,用实例对顶空法的适用性进行了探讨.顶空分析技术具有样品预处理简单、避免大量液相基体干扰、不易沾污或损坏色谱柱、检测灵敏度高等特点,尤其适用于具有高挥发性、高气液相分配比的物质;并且提高水相中的无机盐浓度,可以显著提高被测物质的响应值.但是对于非均相的乳液状态的样品,顶空分析技术不适用.该技术用于废水中痕量全氟异丁烯(PFIB)含量的测定,检测限达到0.04 mg/m3.     

工业废水易挥发有机污染物种类和含量的测定

建立了静态顶空——气质联用结合亨利定律测定某工厂待排放工业废水中易挥发类有机物的种类和含量的检测方法。通过静态顶空进样方式,对工业废水液面以上的混合气体进行气质联用分析,确定废水中有机物的种类和含量。采用1.5×10~(-3) mol/L环己烷为内标,利用混合气体各组分峰面积,通过Henry定律,计算出废水中有机物的含量,并转换为化学需氧量(COD),与国家排放标准进行对比。结果表明,该工厂待排放工业废水的COD值为395.31mg/L,达到国家工业废水三级排放标准(<500mg/L)。     

顶空-气质联用色谱法测定空气清新剂中可挥发性有机物含量

建立气质-顶空自动进样系统联用测定空气清新剂中37种可挥发性有机物含量的检测方法。对样品的取样方法和气质条件进行优化。在优化的条件下,样品中各个可挥发性有机物得到良好的分离,并以外标法定量。本方法精密度高,线性相关系数不小于0.996;加标回收率为80%～120%; RSD均小于10.0%;最低检出限为0.003～3.06μg/g。     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。