ICP-OES法测定PVC制品中6种有害重金属元素

样品在微波辅助加热消解,应用电感耦合等离子体发射光谱法(ICP-OES)同时测定聚氯乙烯(PVC)制品中镉、铅、汞、铬、砷和锑6种重金属元素含量。优化了微波辅助消解温度、雾化气(Neb)流速等测试条件,6种元素仪器检出限在2～10 mg/kg,7次重复性相对标准偏差(RSD)在0. 51%～1. 05%,加标回收率在90. 82%～106. 70%。实验测定了8个PVC制品,其中7个样品中有镉元素检出,部分样品中有铅、铬和锑等元素检出。镉最大检出量为578. 5mg/kg。该方法快速、准确,适用于PVC制品中6种有害重金属元素同时测定。     

ICP-MS法测定羌活中5种重金属及有害元素的研究

采用微波消解法进行样品前处理,并用电感耦合等离子体质谱法进行测定。铜、砷、镉、汞、铅5种元素在相应范围内线性良好(r0. 999),精密度良好(RSD6%,n=6),各元素加样回收率为89. 5%～113. 0%。样品中镉元素含量较高,其它4种元素的含量都处于较低水平。此方法体系简单、快速准确,适用于羌活药材中重金属及有害元素的质量控制分析。     

ICP/MS碰撞反应模式测定土壤和沉积物中V、Pb等11种元素

采用王水回流法萃取土壤样品,在碰撞模式及碰撞反应模式下,以内标法进行ICP-MS测定,并计算方法检出限、长期稳定性等。测试结果为:V、Cr、Ni、Cd、Pb等11种元素方法检出限在0. 026～0. 27 mg/kg之间,测定下限在0. 11～1. 07 mg/kg之间,2 h内稳定性在0. 57%～2. 35%之间;内标元素Rh在He+NH_3模式及He模式下2 h内的稳定性分别为1. 97%及1. 17%。表明ICP-MS2000B附带的碰撞反应池可有效地消除氯离子和其他多原子离子干扰,符合土壤中重金属元素含量的测试要求。     

粉煤灰中痕量重金属质谱分析的研究

研究了微波消解样品,试液用ICP-Ms法同时测定样品中Pb、As、cd、Cr、Ni等重金属元素。对影响其测量的各种因素进行了较为详细的研究,确定了实验的最佳测定条件。结果表明,方法的检出限为0．001．0．008μs／L,回收率为92．98％-109．12％,RSD小于2．89％。该法准确、快速、简便,应用于粉煤灰中重金属元素的测定,结果满意。     

ICP-MS法测定涂料中痕量重金属的研究

研究了微波消解样品，试液用电感耦合等离子体质谱(ICP-MS)法同时测定样品中Pb、As、Cd、Cr、Ni等重金属元素。对影响其测量的各种因素进行了较为详细的研究，确定了实验的最佳测定条件。结果表明，方法的检出限为0．001～0．008μg／L，回收率为91．90％～104．02％，RSD小于1．15％。     

微波消解ICP-MS同时测定复杂样品中6种重金属及聚类分析

选用九里香原料建立微波消解ICP-MS法同时测定复杂样品中6种重金属(Pb、Cd、Cu、Hg、As、Cr)含量的方法。结果表明,通过系统聚类分析,6种重金属元素的线性相关系数均大于0. 996,平均加样回收率在91%～98%之间,RSD在4%之内。不同批次的九里香药材中各种金属元素含量差异较大,建立的方法具有操作简单,分析速度快,准确度高等优点,可以用于复杂植物原料样品中多种重金属的含量测定,在制药工业生产中对原料安全性保障具有实践意义。     

涂料中重金属元素测定的研究

采用电感耦合等离子体原子发射光谱(ICP-AES)法并结合微波制样技术,测定涂料中有毒重金属元素。对影响其光谱测量的各种因素进行了较为详细的研究,确定了试验的最佳测定条件。结果表明,方法的检出限为0.05～0.001μg/ml,回收率为87.68%～116.23%,RSD小于2.27%。该法准确、快速、简便,应用于涂料中有毒重金属元素的测定,结果满意。     

ICP-OES法测定矿井废水中6种重金属元素

矿井废水是地表水及地下水的主要重金属污染源之一,以某市7个具有代表性的(A、B、C、D、E、F、G)的矿井废水为实验样品,建立了电感耦合等离子体原子发射光谱法ICP-OES法同时测定水中多种重金属元素的分析方法,实验结果表明,各元素标准曲线的相关系数均能达到0.999,检出限均小于0.1mg·L~(-1),且通过精密度实验得到各元素含量的RSD为0.512%～2.702%,在加标回收率试验中各元素加标回收率在94.6%～102.2%之间。说明该方法的线性范围较广、检出限较低,精密度、加标回收率均能满足检测需求,具有一定的推广性。使用该方法测定矿井废水,实验结果表明,各矿井废水中均有不同程度的重金属元素检出,其中铁锰的重金属含量占比较高。     

氢化物发生--原子荧光法测定痕量硒

研究了氢化物发生 -原子荧光法在生物、农业、环境等样品中硒含量测定上的应用 ,考察了HCl介质浓度、HCl载流浓度、KBH4浓度、仪器工作参数、共存元素等条件的影响 ,确定了最佳测定条件。方法的检出限 0 .32 μg/L ,相对标准偏差小于 0 .4 % ,回收率为 93%～ 10 2 %。     

ICP-MS测定铅锌混合矿中铜、 砷、 镉元素的含量

采用微波消解法以盐酸-硝酸-氢氟酸溶解样品,用电感耦和等离子体发射光谱质谱法测定铅锌混合矿中铜、砷、镉、锑元素,并用~(103)Rh作为内标元素补偿基体效应和灵敏度漂移。同时对样品前处理条件、同位素和内标元素选择等进行了探讨。在最佳实验条件下,检出限为0. 01～1. 43μg/g,使用该方法分析样品,测定结果与化学法分析值吻合,各成分测定值的相对标准偏差(n=6)在0. 53%～5. 39%之间。完全满足铅锌混合矿的检测需要。     

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。