催化动力学分光光度法测定纯铝中痕量铜

依据动力学理论用分光光度法测定纯铝中痕量铜,利用铜(Ⅱ)在中性介中催化加速过氧化氢氧化锌试剂褪色这一反应建立了测定痕量铜(II)的新方法。测铜(Ⅱ)时,在范围为0—2.0×10-7g·mL-1内符合Beer定律,最低检测限为1.2×10-9g·mL-1,表观摩尔系光系数ε为1.28×104L·mol-·1cm-1。此方法用于测定纯铝中的痕量铜快速、简便,准确度高。相对标准偏差在0.15%—3.9%之间。     

还原偶氮胂Ⅲ催化动力学光度法测定痕量铜(Ⅱ)

在邻苯二甲酸氢钾-盐酸缓冲介质中,以1,10-邻菲哕啉为活化剂,痕量铜(Ⅱ)能灵敏催化抗坏血酸还原偶氮胂Ⅲ褪色的反应,以此建立了测定痕量铜(Ⅱ)的新方法。方法的线性范围为0～100ng·(25mL)~(-1),检测限为2．81×10~(-10)g·mL~(-1)。直接用于人发中铜的测定,结果满意。     

ICP-OES测定铜尾矿中的铜铅锌银

为准确快速地检测铜尾矿中的铜铅锌银,选择电感耦合等离子体原子发射光谱仪(ICP-OES)对其进行测定,对实验条件、方法检出限、精密度和加标回收率做了研究。铜尾矿样品经氢氟酸-盐酸-硝酸分解后,用ICP-OES同时测定铜铅锌银4种元素,方法的检出限为0.000 62～0.003 5μg·m L-1,精密度为0.67%～3.08%,回收率为90.0%～110.0%。     

催化光度法测定痕量铜的研究

1　前言铜是生命机体中不可缺少的微量元素之一 ,广泛分布于植物、动物组织及所有食品及饮用水中 ,因此环境及生命组织中痕量铜的测定及研究日趋引起人们的重视[1 ] 。用催化动力学方法测定微量铜的反应体系已有报道 ,但基于Ｈ2 Ｏ2 氧化三苯甲烷类酸性染料的铬天青Ｓ(ＣＡＳ)为指示反应的催化光度法测定痕量铜 (Ⅱ )尚未见报道。本文研究了在活化剂邻菲罗啉 (ｐｈｅｎ)存在下 ,铜 (Ⅱ )对Ｈ2 Ｏ2 氧化ＣＡＳ的催化褪色反应 ,找到了影响催化褪色反应的最佳条件 ,建立了测定痕量铜 (Ⅱ )的新方法 ,测定的线性范围为 0～ 40ｎｇ/ｍＬ ,用于测…     

铜(Ⅱ)-抗坏血酸-硫酸-硫氰酸钾极谱络合吸附波研究

用单扫描极谱法研究了Cu(Ⅱ)-H2SO4-硫氰酸钾体系的伏安行为,发现铜(Ⅱ)在抗坏血酸-H2SO4-硫氰酸钾试剂存在下,于-0.55 V(vs·SCE)左右产生一尖锐、灵敏的极谱波。经实验确定的最佳测定条件为:2.5 mol·L-1硫酸2m L,1%硫氰酸钾2 m L,10%抗坏血酸5 m L,铜(Ⅱ)的浓度在6.250×10-7~4.375×10-6mol·L-1范围内与相应的峰电流成线性关系好,回归方程为ip=348.98CCu(mol·L-1)-283.64,线性相关系数R为0.9993;最小检出浓度为4.0×10-7mol·L-1。方法用于人发中铜含量的测定,测定值与原子吸收光谱法测定值基本一致,相对标准偏差(n=6)为2.7%~4.1%,加标回收率96.2%~102.3%。     

铜含量测定方法研究

建立二乙基二硫代氨基甲酸钠(DDTC或铜试剂)光度法测定铜含量的方法。实验结果表明,在pH值4～5的条件下,Cu-DDTC配合物的最大吸收波长为460 nm,摩尔吸光系数为1.0×104L/(mol.cm),线性范围为0～2.4μg/mL,加标回收率为94.9%～104.1%,RSD为3.1%～5.7%。该方法可用于样品中常量铜的测定,并且大量的银存在时也不干扰铜的测定。经用于银包铜粉样品中铜含量的测定,结果符合要求。     

催化动力学光度法测定痕量铜

研究了在磷酸介质中α ,α’ -联吡啶存在下 ,铜 (Ⅱ )催化过硼酸钠氧化中性红使其褪色这一新的指示反应及其动力学条件 ,建立了灵敏地测定痕量铜 (Ⅱ )的新方法。该方法的线性范围 0～ 2 5 μg/L ,检测限为 2 0× 10 -6g/L。用于合金中铜 (Ⅱ )的测定 ,结果令人满意     

吖啶红荧光猝灭法测定水样及果皮中的痕量铜

磷酸盐缓冲介质中,痕量Cu(Ⅱ)对过氧化氢氧化吖啶红的反应具有催化作用,导致吖啶红在550nm处的荧光强度发生明显的猝灭,以此建立了测定痕量铜的新方法。在最优化条件下,方法的线性范围为8.0×10-4~9.2×10-3μg·mL-1,检出限为7.3×10-4μg·mL-1,用于水样及果皮样品中痕量Cu(Ⅱ)的测定,回收率在97.5%~103.5%之间。在40℃条件下,猝灭反应的活化能Ea=87kJ·mol-1,表观速率常数k=1.05×10-3s-1,且Cu(Ⅱ)对体系的荧光猝灭属动态猝灭。     

铜-镍合金镀液中铜(Ⅱ)和镍(Ⅱ)的测定

在pH=8.0的氨-氯化铵缓冲溶液和组成为OP乳化剂、正丁醇、正庚烷和水的微乳液中,以2-(5-溴-2吡啶偶氮)-5-二乙氨基酚为显色剂,通过测定铜(Ⅱ)、镍(Ⅱ)配合物共存体系的吸光度A,及加入乙二胺掩蔽铜(Ⅱ)后镍(Ⅱ)配合物的吸光度A1,得到铜(Ⅱ)配合物的吸光度A2=A-A1,从而求出铜(Ⅱ)、镍(Ⅱ)含量,用于Cu-Ni合金镀液中铜(Ⅱ)、镍(Ⅱ)的测定,效果良好.     

电解电渗析联合处理含铜废水

研究了电解电渗析联合处理含铜废水的可行性.结果表明:电解铜回收率随电压和进水质量浓度升高、进水流量降低而提高.在U=4.5 V,p(Cu2+)进水为500 mg/L,q进水为1 L/h时,铜最高回收率为70%,能耗是11(kW·h)/kg.电解后尾液再经电渗析继续处理,淡水中铜的去除率约为98%,浓水的浓缩倍数在2以上,能耗为0.9～3.0(kW·h),可再进行电解回收.经X-射线衍射仪观察,回收铜几乎为100%,回收铜的粒径随电流密度增加而增加.     

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.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008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、不饱和聚酯树脂、环氧树脂)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.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006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生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。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（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。