蒸发浓缩-火焰原子吸收法测定水中铅镉

原子吸收法是水质检测中测定铅、镉的主要方法之一,通过蒸发浓缩—火焰原子吸收法测定水中铅镉,有效扩大了直接吸入—火焰原子吸收法的测量范围。     

密封微波溶样导数火焰原子吸收法测定中成药阿胶中的铜、锌、锰

本实验用密封微波溶样技术对中成药阿胶样品进行了预处理,以导数火焰原子吸收法测定了其中所含的微量元素铜、锌、锰。结果表明,与常规样品消化方法相比,微波样品处理技术具有方便、快捷、污染少、消化完全等特点;而导数测量装置与火焰原子吸收分光光度计的连接使得测定的灵敏度大为提高,检测限大幅度降低,测定的精密度也得以改善。     

原子捕集火焰原子吸收法测定工业废水中痕量铅

建立了一种原子捕集火焰原子吸收光谱测量工业废水中痕量铅的方法。原理如下 :捕集管内通冷却水 ,原子蒸汽遇冷凝集在管子外表面 ,捕集一定时间内 ,迅速停止冷却水 ,管温剧烈上升 ,使管子外表面的原子迅速蒸发 ,产生一个强的峰型吸收信号 ,根据信号与浓度呈线形关系进行定量分析。该方法捕集 4min测铅特征质量浓度为 3.72× 10 -3 mg/L ,检出限为 0 .0 11mg/L ,灵敏度比常规法提高了 114倍 ,6次测量的相关系数为 0 .99     

在线离子交换预富集-火焰原子吸收光谱法测定环境水样中的铅和镉

采用在线离子交换预富集-火焰原子吸收光谱法同时测定环境水样中微量铅和镉。观察样品pH、洗脱剂浓度、离子交换树脂用量、共存离子对离子交换树脂富集效果的影响。结果表明,当交换树脂用量为0.50 g,样品液pH为6.0时,用0.80 mol/L HNO3进行洗脱可达到良好效果。方法用于在线分离和富集环境水样中的铅和镉,对铅和镉的测定灵敏度提高了100倍,加标回收率为90%～102%。在线离子交换预富集-火焰原子吸收光谱法具有操作简便,灵敏度高,成本低等特点,可用于环境水样中微量重金属的现场快速检测。     

浊点萃取火焰原子吸收法测定水样中痕量铅的研究

以浊点革取-火焰原子吸收光谱法测定痕量铅,探讨了实验条件对浊点草取及测定灵敏度的影响。在最佳条件下,铅富集倍数达到20倍。该方法可用于自来水、井水及河水中痕量铅的测定。     

火焰原子吸收光谱法测定痕量铅的研究与应用

综述了近年来火焰原子吸收光谱法测定痕量铅的研究进展。从火焰原子吸收光谱法在环境、食品及其它样品中铅的测定分析进行了归纳和评述,展望了火焰原子吸收光谱法测定痕量铅未来的研究方向和发展前景。     

乙酸丁酯萃取—火焰原子吸收收测定含量较低的银

以乙酸丁酯为萃取剂,利用火焰原子吸收测定化探样品及水样中痕量银的方法。此方法能有效提高火焰原子吸收测定银是的灵敏度及测量时的精密度及准确度,此方法简便快速、准确、重现性好,适合大批量样品测定。     

日用陶瓷中铅镉溶出量的测定

采用火焰原子吸收分光光度法（AAS）来测定日用陶瓷中铅镉的含量,并对测量结果进行分析。结果表明：方法检出限分为0.21μg·mL-1（Pb）和0.007μg·mL-1（Cd）,回收率为102.45%和94.67,精密度为2.10%和3.14%。该方法灵敏度、准确、快速、检出限低,适用于实验室中微量的铅、镉含量的测定。     

用开缝石英管火焰原子吸收光谱法测定工业氯化铵及碳酸氢铵中铅的研究

样品经升华分解处理后,在有大量钾存在的情况下,用乙炔火焰原子吸收法,采用开缝石英管进行测定,取得了满意的结果。灵敏度提高8倍左右,其方法的平均回收率为101.8%,标准偏差为0.011,相对标准偏差为2.0%。用本方法测定铅的灵敏度达到并超过了国内先进水平。     

火焰法原子吸收分光光度计灵敏度的改善方法

在火焰法原子吸收分光光度的检定中经常会遇到一个问题就是灵敏度较低,那么如何改善火焰法原子吸收分光光度计的灵敏度是本次论文的主要目的。本论文通过运用对喷雾器的调整,来提高雾化质量,同时利用灯的电流、空心阴极灯的位置、狭缝宽度、光束等相对位置的调整,从而提高原子吸收分光度计的灵敏度。     

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.     

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.     

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。