电热板-ICP-AES法分析土壤中总铬的方法优化

在测定土壤中总铬的含量时,结果往往低于比标准值。本实验通过改进消解方法,解决了在消解过程中Cr元素的损失问题。通过在消解过程同步进行样品加标实验,并进行加标校正,解决了基体效应对样品测试结果的影响。结果表明,改进后的方法中,所有标准土壤样品分析结果均在保证值范围内,其变异系数处于1.0%～1.4%,该方法适合用于土壤中总铬的测定。     

微波消解-氢化物发生-原子荧光光谱法测定大米中硒

探讨微波消解前处理,氢化物发生原子荧光光谱法测定土壤污染详查土地大米中硒含量的分析方法。大米样品先用硝酸和过氧化氢进行微波消解,而后上机测定消解液。实验优化了样品前处理条件和仪器测定条件,解决了消解液中待测元素硒挥发损失、前处理时间长等问题。方法经生物成分分析标准物质验证,结果与标准值吻合。用本方法硒的检出限为0.005μg/g,精密度小于7%。该方法操作简单、快速、结果准确可靠,应用于实际样品的检测,结果满意。     

ICP-MS法测定土壤中金属元素

在微波条件下,采用HCl-HF-HNO3-H2O2体系消解土壤样品,使用ICP-MS法对其中几种金属元素的含量进行测定。设计了适当的实验方法,选择了合适的实验条件,并与ICP-AES法的测定结果进行了对比,最后与标准物质的参考值比较。实验结果表明,样品中的Cr、Co、Ni、Mn、Cu、Pb、Zn、Mo、Cd的测定值与标准值一致,使用这两种分析方法测定经微波消解的样品,结果均令人满意,但不同方法测定不同元素各有优势。可为多金属岩石矿物的分析测试提供方法经验和数据参考。     

微波消解测定土壤重金属体系的研究

对微波消解测定土壤金属元素的标准曲线绘制方式进行了研究。以铜元素为例,分别使用金属标准使用液和土壤标准样品消解液进行标准曲线的绘制,结果表明:在测定土壤样品时,直接用标准使用液绘制标准曲线,土壤带标测定结果都偏低,测定误差10%以上;用土壤标准样品消解液作为标准曲线进行带标测定,土壤带标测定结果在标准范围内。本方法避免了土壤样品因消解不完全而产生的误差,能够提高土壤金属样品分析的准确率。     

高压密闭消解-ICP-AES法在农产品分析8种元素中的应用

为了达到快速、准确的测定大批量农业产品中多种元素含量的目的，建立了基于密闭消解前处理方式结合电感耦合等离子体发射光谱法同时测定农产品中K、Na、Ca、Mg、Fe、Al、S、P元素的方法。通过谱线干扰试验，确定了S、P的最佳分析谱线，极大地提高了分析的准确性。并对消解酸试剂、消解温度、消解时间等实验条件进行探讨，建立了最优密闭消解条件。考察了方法的标准曲线线性关系、检出限、准确度和精密度，结果表明：在最优的实验条件下，在一定的浓度范围内所分析的8种元素具有良好的线性关系，线性相关系数R²达到0.999以上。选择农产品国家标准物质GBW10010(大米)、GBW10011(小麦)、GBW10014(圆白菜)、GBW10015(菠菜)进行方法验证，方法检出限范围为0.007～0.11μg/g,相对误差RE为-2.91%～1.87%,相对标准偏差RSD为0.15%～4.40%。采用本实验方法进行实际农产品的加标回收实验，回收率为91%～109%。实验方法能够实现同时大批量、快速、准确的测定农产品中8元素的含量。     

微波消解-ICP-OES法测定铁矿石中 K、Na、Pb、Zn、As、Sn

通过实验研究了电感耦合等离子体发射光谱法(ICP-OES法)测定铁矿石中残余元素钾、钠、铅、锌、砷、锡的分析测试条件。采用微波消解仪消解试样，选用元素最佳分析谱线和仪器合适的工作条件进行测定。共存元素之间的干扰很小，测定值相对标准偏差小于9%,加标回收率在93%～113%之间，标样测定结果与认定值相符合，分析方法快速、简便，分析结果准确。     

自动石墨消解-原子荧光法同时测定土壤中砷、汞、硒

本文采用自动石墨消解仪对土壤样品进行消解前处理,原子荧光法测定土壤中砷、汞、硒3种元素的含量。实验结果表明,砷、汞、硒在0.20～20.0μg·L-1范围内线性相关系数均大于0.999,方法的检测限分别为0.00、0.002、0.005mg·kg-1,本方法测定GSS-4土壤标准样品的结果在样品定值范围内,7次检测结果的相对标准偏差为2.32%～4.89%。本方法操作简单,灵敏度高,检出限低,重现性好,测定结果准确可靠,适合于大批量土壤样品中砷、汞、硒的测定。     

铜阳极泥脱铜渣中金、银、钯含量测定

建立了连续测定铜阳极泥脱铜渣中金、银、钯含量的分析方法,并与火试金法进行比较。首先,利用硝酸+乙二胺四乙酸（EDTA）+酒石酸消解铜阳极泥脱铜渣,得到含有银、钯和少量金的消解液,考察了硝酸、EDTA和酒石酸用量对消解效果的影响。结果表明,硝酸、EDTA和酒石酸用量分别为30mL、3mL、1.5g时,消解效果最好。然后,利用王水对残渣进行二次消解,得到含有金和少量银、钯的消解液,考察了王水用量对消解效果的影响。结果表明,王水用量为15mL时即可完成消解。最后采用火焰原子吸收光谱仪测定消解液中的金、银、钯含量。采用本方法测定铜阳极泥脱铜渣,Au、Ag、Pd各元素相对标准偏差均小于1%（n=10）,加标回收率在95.57%～98.70%之间,实验结果准确可靠、重现性好,与火试金法测定结果相一致。     

电感耦合等离子体质谱法测定土壤中的镉

目前对于土壤中微量污染元素镉的国家及环境方法标准尚不足以满足监测需求。本实验建立了电感耦合等离子体质谱法测定土壤中的镉的分析方法,实验中样品以HCl,HNO_3,HF和HClO_4四酸消解体系于电热板上加热消解处理,分析中使用在线标准Rh加入法定量,内标回收率为79%～86%,有证土壤标准物质测定结果均在证书规定范围内,所有样品结果RSD为0.9%～1.4%。本方法结果准确稳定,可作为制定相关标准的参考基础,同时适用于长时间大规模土壤的分析监测。     

超声波消解测定土壤中锑、铍的方法

对土壤样品先进行超声波消解,再使用电感耦合等离子体原子发射光谱(ICP-AES)对锑、铍元素进行测定;样品加入硝酸、氢氟酸经超声波消解,再高氯酸冒烟飞除硅。在5%的盐酸介质中,于优化后的仪器条件下测定锑、铍元素。本方法方法回收率在93.0%~102.5%之间,方法标准偏差小于3.0%,该方法流程简便,分析快速,结果较准确。     

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.     

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。     

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.