烟梗草木灰中微量金属元素含量分析

烟梗草木灰是属于农作物秸秆草木灰之一,含钾丰富,除此之外它还含有铜、铁、锌、锰、钙、镁、铅、铬、镉、汞、砷等微量金属元素。本文利用微波消解-原子吸收法及微波消解-原子荧光法对烟梗草木灰中微量金属元素含量进行测定,结果表明:烟梗草木灰中,各微量元素的含量分别为含量分别为铁(1. 46%)、铜(0. 14%)、锌(0. 18%)、钙(5. 16%)、镁(1. 87%)、锰(0. 0575%)、铅(0. 0525%)、镉(0. 0075%)、铬(0. 0375%)、汞(0. 0004%)、砷(0. 0035%)。烟梗草木灰中含钙、铁、镁含量丰富,重金属铅、镉、铬、汞、砷含量在国家标准(GB/T 23349-2009)限量范围之内。     

FAAS测定玉米须等四种中药材的金属元素含量

采用火焰原子吸收光谱法(FAAS)测定了玉米须、沙棘、肉豆蔻和地龙四种中药材中的铜、钠、铁、钾、镁、钙、锰、锌、锶、铅、铬、镍、镉、钴元素含量,相对标准偏差均低于5.43%,方法加标回收率在95.4%～104.9%。结果表明,玉米须、沙棘、肉豆蔻和地龙中均含有较高的钾,其中玉米须镁含量较高,沙棘和肉豆蔻中钙、镁含量较高,地龙中钙、铁、镁含量较高。可为探讨玉米须、沙棘、肉豆蔻和地龙中金属元素含量及其测定方法等提供科学依据。     

火焰原子吸收法测定花粉中几种金属元素的含量

目的测定花粉中7种金属元素的含量,证明花粉中含有丰富的营养物质,探讨花粉与人体健康的关系。方法首先对样品进行湿法消解,采用火焰原子吸收法对处理后的样品中的铜,铁,锌,锰,镁,钙,铅7种元素进行直接定量分析测定。结果花粉中铁,锌,锰,镁,钙的含量相对较为丰富,此外铅在样品中也有一定的含量。结论该方法样品的加标回收率为98-118%,相对标准偏差为0.86-2.47%。此种方法测定花粉中7种金属元素的含量,操作简单,精密度、准确度高。     

微波消解-等离子体发射光谱法测定蒙药敖西根-18和哈日-嘎布日-10中的多种元素含量

采用HNO3∶H2O2(体积比2∶3)为溶样试剂,以微波消解和电感耦合等离子体原子发射光谱法(ICP-AES)联用,同时测定了蒙药敖西根-18和哈日-嘎布日-10中的铝、钛、汞、铜、铅、锌、镉、砷、钡、铁、磷、锡和钙元素的含量。结果表明,在最佳实验条件下,在0.3 g蒙药中各元素的回收率为97.5%～104.2%,RSD<2.1%,检出限介于0.015～10.2μg/L,该方法简便、迅速、准确度和精密度高,适用于蒙成药中这13种元素的同时测定。     

原子吸收光谱法测定中药材中14种金属元素

以微波消解法处理中药样品,用火焰原子吸收光谱法测定山药、甘草、天冬、五味子4种中药中的钾、钠、镁、钙、铁、钴、镍、铜、锌、锰、锶、铬、镉和铅元素含量。中药样品以5 mL HNO3和1 mL H2O2在一定的温度和时间下经微波消解处理后,在最佳工作条件下测定以上14种金属元素含量,各元素的加标回收率在95.3%~105.6%之间,标准工作曲线的线性相关系数均大于0.999,该方法测定结果的相对标准偏差为0.69%~4.38%(n=10)。该方法适用于中药材中金属元素的含量测定。     

ICP-AES法测定山西地区几种醋中的金属元素

采用HNO_3微波消解法对山西地区生产的几种醋的样品进行处理,利用ICP-AES仪测定样品中钙、钾、镁、锌、铁、铜、铬、锰、镍等9种金属元素的含量。实验结果表明,这几种醋中均富含钙、钾、镁、锌、铁、锰等对人体有益的金属元素,铬、镍等有害元素含量低于食品安全国家标准食品中污染物限量。该方法回收率在85%~102%,相对标准偏差≤2.97%,检出限介于0.001μg/mL~0.174μg/mL。为指导人们合理膳食提供科学依据。     

ICP-MS法同时测定高纯工业品三氯氧磷中28种金属元素

建立了ICP-MS法同时测定高纯工业品三氯氧磷中铝、锑、砷、钡、铋、镉、钙、铬、钴、铜、镓、铁、铅、金、锂、镁、锰、汞、镍、铌、钾、银、钠、锡、锶、钛、钒、锌等28种元素含量的方法。采用标准加入法及碰撞反应池技术消除干扰,确立了最佳测定条件。结果表明检出限低(0.004~0.174μg/L)、精密度高(1.0%~5.9%)、回收率好(89.0%~115.8%)。本方法重复性好、无复杂前处理步骤、灵敏度高、操作简便,完全适用于高纯工业品三氯氧磷中28种金属元素的同时测定。     

碰撞反应池等离子体质谱法同时测定高纯工业品三溴化硼中27种金属元素

目的:建立了电感耦合等离子体质谱法(ICP-MS)同时测定高纯工业品三溴化硼中铝、锑、砷、钡、铋、镉、钙、铬、钴、铜、镓、金、铁、铅、锂、镁、锰、汞、镍、钾、银、钠、锡、锶、钛、钒、锌的方法。方法:采用标准加入法及碰撞反应池技术消除干扰,确立了最佳测定条件。结果:检出限为0.003~0.166μg/L,精密度为1.0%~6.4%,回收率在88.8%~114.8%之间。结论:本方法无复杂前处理步骤、重复性好、灵敏度高、操作简便,完全适用于高纯工业品三溴化硼中27种金属元素的同时测定。     

小叶麦冬果实中微量元素的光谱测定

采用空气-乙炔火焰原子吸收法,对小叶麦冬果实的钙、钠、镁、锌、锰、铜、钾、铁8种元素进行了含量的测定。选择了最佳电离抑制剂和酸性介质。本实验以氯化铯为电离抑制剂,盐酸浓度控制在2%以内,用氯化锶消除磷酸对钙的干扰,使吸光值稳定,用标准曲线法进行测定,获得了满意的效果。该测定方法简便、快速、准确。结果表明,小叶麦冬果实中钾、钙等微量元素含量丰富,含钾17.09mg/g、钙8.22mg/g。     

硫酸镍溶液产品中11种微量元素ICP-OES同时测定

用ICP-OES法测定硫酸镍溶液产品中的钙、镉、钴、铬、铜、铁、镁、锰、钠、铅、锌11种元素含量,用钇作内标校正大量镍基体的干扰。方法检出限可满足日常分析的需要。加标回收率93.9%～105%;相对标准偏差0.34%～3.21%。方法简便、快速、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.     

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.     

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。