催化动力学光度法测定痕量的碘

经研究发现,在稀盐酸介质中,溴酸钾氧化中性红能使其褪色.加入碘离子后,碘离子对该氧化褪色反应又有明显的催化作用.同时又研究了该催化褪色反应的动力学条件,包括酸度,试剂的用量,温度,时间对反应的影响,以及共存离子的干扰.从而建立了一种新的快速测定痕量碘的动力学光度法.该方法的线性范围为(0.02-0.08)μg/L,检出限为4×10-9g/L,回归方程,△A=0.0265C(μg/L) 0.024相关系数r=0.9995.该方法简便、灵敏、准确、选择性好,用于水及蔬菜中痕量碘的测定,均获得了令人满意的效果.     

电感耦合等离子体质谱法测定饮用水中的碘

建立了电感耦合等离子体质谱测定饮用水中碘的方法。以碲作为在线内标,采用四甲基氢氧化铵稀释饮用水后直接用电感耦合等离子体质谱检测。结果表明本方法检出限为0.1?g/L,方法在0~100?g/L线性良好,相关系数为1.000。对纯净水、自来水和矿泉水进行检测,碘的相对标准偏差(RSD)均小于5%,不同样品的回收率在95%~105%之间。该方法具有检出限低、线性范围宽、精密度好、准确度高等优点,能准确快速测定饮用水中的碘。     

衍生气相色谱法测定草酸艾司西酞普兰中甲磺酸烷基酯类

目的:建立衍生气相色谱法同时检测草酸艾司西酞普兰中甲磺酸甲酯、甲磺酸乙酯、甲磺酸异丙酯三种甲磺酸烷基酯。方法:采用Na I-H2O碘化衍生,利用DB-WAX毛细管柱(30m*0.45 mm,0.85 um)分离,氢火焰离子化(FID)检测器。结果:碘甲烷线性范围为0.2784～10.44μg/mL,碘乙烷线性范围为0.2944～11.04μg/mL,2-碘丙烷线性范围为0.2608～9.78μg/mL。该方法专属性、准确度等指标均符合要求。结论 :本方法可用于测定草酸艾司西酞普兰中的甲磺酸甲酯、甲磺酸乙酯、甲磺酸异丙酯三种甲磺酸烷基酯成分的同时碘化衍生分离分析,方法简便、结果可靠、重现性好。     

火焰光度法测定载体氧化铝中钠含量

研究了钯催化剂载体氧化铝中微量钠的火焰光度法测定,确定了较适宜的测定条件,其Na~+的检出浓度为0.1μg/ml,线性范围为1.0～36μg/ml。方法简便快速、准确度高,精密度好,回收率为96.4％～100.6％,最大变异系数为0.7％。     

分光光度法测定锌-锰电镀液中微量镉

采用镉(II)-碘化钾-罗丹明高灵敏度显色体系,直接测定锌-锰电镀液中的微量镉。镀液中Cd(II)的检出限为0.59μg/L,回收率为96.5%～103.3%,线性范围为0～0.18μg/mL,相对标准偏差RSD≤3.23%(n=8)。该方法无需分离基体,结果准确、快速,能满足实际生产的要求。     

气相色谱法测定化妆品中的多元醇保湿剂

建立了气相色谱(GC)同时测定化妆品中5种多元醇(1,2-丙二醇、乙二醇、1,3-丁二醇、二甘醇和甘油)保湿剂的方法.试样用甲醇提取过滤后,采用GC对样品进行定量分析.结果显示,5种多元醇保湿剂的质量浓度与其相应的峰面积呈线性关系,线性范围分别为10 μg/mL～1 200 μg/mL(1,2-丙二醇和1,3-丁二醇),10 μg/mL～1 100 μg/mL(乙二醇),10 μg/mL～1 000 μg/mL(二甘醇),10 μg/mL～1 300 μg/mL(甘油),相关系数r＞0.99.应用此法测定化妆品中5种多元醇保湿剂的质量分数,回收率在93.6%～102.4%,相对标准偏差为0.84%～1.75%.该方法简便快速,结果稳定准确,可用于化妆品中多元醇保湿剂含量的质量控制.     

微波消解原子荧光光度法测定花生样品中的汞

采用微波消解技术—原子荧光光度法测定花生样品中痕量 Hg.方法检出限为0.0004μg/g,线性范围:0.001~6μg/g,相关系数 r=0.99995,相对标准偏差(RSD,n=7)4.84%~5.30%,加标回收率在91%~114%之间.实验证明:花生中有害元素 Hg 的含量远低于我国粮食(成品粮)总 Hg 允许限标准.方法简便、快速,结果准确、可靠,能够满足花生样品中痕量 Hg 的测定.     

Determination of phenylhydrazine hydrochloride in industral wastewater by HPLC

通过实验建立了工业废水中盐酸苯肼的高效液相色谱分析方法.色谱条件为:Kromasil-Ct8( 150 mm×4.6 mm,5μm)色谱柱,流速1 mL/min,柱温30℃,进样体积10μL,流动相为V(甲醇)∶V(8mmol/LKH2PO4+4 mmol/LK2HPO4)=35∶65,测定波长235 nm.测定结果表明,线性范围为0.1～100 mg/L,平均加标回收率为98.2％,相对标准偏差为1.06％.该方法操作简单,分析快速、准确.     

原子吸收法测定癸二酸二丁酯中微量钠

以丙酮-水溶液为介质,用原子吸收法测定癸二酸二丁酯中钠含量,操作简单方便、快速准确。其线性范围为0～1.0μg/ml,灵敏度为0.0084μg/ml/1％,检测限为0.0012ug/ml,回收率为95～105％。     

离子色谱测定铬酸钾中微量硫酸根和氯离子

建立了一种用于测定化学试剂铬酸钾中的微量硫酸根和氯离子抑制型离子色谱分析法.采用3.2 mmol/L碳酸钠和1.0 mmol/L碳酸氢钠溶液作为缓冲液,流速0.7 mL/min、4 mL/L稀硫酸水溶液作为抑制再生液,进样体积20 μL.该法建立的氯离子和硫酸根离子的线性范围分别为0.01 ～1.0 mg/L和0.1～10.0 mg/L,线性系数r均＞0.999,氯离子和硫酸根离子的检出限为0.5和5 μg/L(以溶液浓度计),精密度分别为2.15％和1.94％(n=8),加标回收率分别在99.2％～100.0％和97.9％～99.9％.该法操作简单、准确、快速.可以用于常规铬酸钾试剂中微量硫酸根和氯离子的定性与定量分析.     

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.     

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。