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1.
白桦  侯永根  倪静安  文珊珊 《化学试剂》2006,28(2):89-90,94
报道了显色剂2,3,7-三羟基-9-(5'-苯偶氮)水杨基荧光酮(PASAF)的合成方法.研究了试剂与钼(Ⅵ)的分光光度性质及反应条件.在0.48mol/L的硫酸介质中,阳离子表面活性剂CTMAB存在下,钼(Ⅵ)与PASAF形成稳定的橘红色配合物,在526nm处有最大吸收,表观摩尔吸光系数为1.46×105L·mol-1·cm-1,钼(Ⅵ)含量在0~10μg/25mL范围内符合比尔定律.该方法直接用于豆类中痕量钼(Ⅵ)的测定,获得满意的结果.  相似文献   

2.
铬(Ⅵ)与DBM-偶氮胂褪色光度法研究   总被引:4,自引:0,他引:4  
提出了一个测定痕量铬(Ⅵ)的新的光度体系。在0.10~0.50 mol/L硫酸介质中,DBM-偶氮胂(DBM-ASA)与铬(Ⅵ)发生氧化褪色反应,褪色后体系在530 nm处产生最大吸收。反应的摩尔吸光系数ε530 nm=4.71×104L/(mol.cm),铬(Ⅵ)质量浓度在0~1.0×10-3g/L遵守比耳定律。用于硝酸铬及氯化铬中痕量铬(Ⅵ)的测定,得到了满意的结果。  相似文献   

3.
研究了新显色剂 4 - (2 -吡啶偶氮 ) -邻苯三酚 (PAPG)与 Zn( )的显色反应。在 p H =8.6的缓冲溶液中 ,该试剂与 Zn( )反应生成稳定的蓝色配合物 ,其最大吸收波长为 6 0 3nm ,对比度 10 3nm,表观摩尔吸光系数为 3.14× 10 4 L· mol- 1 · cm- 1 。Zn( )质量浓度在 0 .0 0 2~ 1.0 4 m g/ L范围内服从比耳定律。该方法应用于人发中 Zn的测定 ,同时用原子吸收法对照 ,结果令人满意  相似文献   

4.
研究了在硫酸介质中用5-Br-PADAP分光光度法测定Cr(Ⅵ)。络合物的最大吸收在590nm,摩尔吸光系数为2.0×10~4,有色物质的组成为Cr_3O_1~(2-):5-Br-PADAP=1:2。1~25μg/25ml符合比耳定律。可用于铬铝钢、水、矿物中铬或Cr(NO_3)_3中Cr(Ⅵ)的测定。是一个测定铬的好方法。  相似文献   

5.
合成了新试剂(2,6-二溴-4-硝基苯)-3-(4-硝基苯)-三氮烯(DBNPNPT)。测定了其亚氨基质子离解常数pKa=9.5。研究了试剂与镉的显色反应,结果表明,在Triton X-100存在下,pH10.6~11.4时,试剂与镉发生灵敏显色反应。用双波长法测定,其表观摩尔吸光系数达2.08×105L·mol-1·cm-1。镉含量在0~10μg/25mL符合比耳定律。  相似文献   

6.
光度法测定镀铬液及铬酸钝化液中Cr(Ⅵ)和Cr(Ⅲ)   总被引:10,自引:5,他引:5  
在硫酸介质中,沸水浴加热条件下,Cr(Ⅵ)能氧化玫瑰桃红R褪色,且褪色程度(ΔA)与Cr( Ⅵ)的质量浓度在一定范围内成正比关系,据此,建立了测定Cr(Ⅵ)和Cr( Ⅲ)的新方法。线性范围为0~8μg/mL,表观摩尔吸光系数为1.7×104L·mol-1·cm-1。该方法可用于镀铬溶液和铬酸钝化液中Cr(Ⅵ)和Cr(Ⅲ)含量的测定。  相似文献   

7.
合成了5,10,15,20-四(3-溴-4-磺酸苯基)卟啉[T(3-BrP)PS_4],测定了试剂的离解常数,pK_(a_(1,2))=3.88,讨论了试剂与锰在 Cd~(2+)、邻菲啰啉和 CTMAB 存在下,于 pH9.2的显色反应。配合物的表观摩尔吸光系数,(?)_444=3.34×10~5L·mol~(-1)·cm~(-1)。锰含量在0~3.0μg/25mL 范围内服从比尔定律。用于茶溶液和草莓酒中痕量锰的测定,结果与 AAS 的一致。  相似文献   

8.
1-(2-苯并噻唑)-3-(4-溴苯)三氮烯与汞(Ⅱ)的显色反应研究   总被引:11,自引:0,他引:11  
赵慧  夏心泉 《化学试剂》2005,27(7):425-426
研究了1-(2-苯并噻唑)-3-(4-溴苯)三氮烯(BTBPT)与汞(Ⅱ)的显色反应。在非离子表面活性剂TritonX-100存在下,于pH10.9的Na2B4O7-NaOH缓冲介质中,Hg(Ⅱ)与BTBPT形成1∶2的稳定配合物。其最大吸收波长是465nm,表观摩尔吸光系数为:1.98×105L.mol-1.cm-1。汞(Ⅱ)在0~12μg/25mL范围内遵守比尔定律。此法应用于水样中Hg2+的测定,获得了较为满意的结果。  相似文献   

9.
报道了显色剂2,3,7-三羟基-9-(5′-苯偶氮)水杨基荧光酮(PASAF)的合成方法。研究了试剂与钼(Ⅵ)的分光光度性质及反应条件。在0.48mol/L的硫酸介质中,阳离子表面活性剂CTMAB存在下,钼(Ⅵ)与PASAF形成稳定的橘红色配合物,在526nm处有最大吸收,表观摩尔吸光系数为1.46×105L.mol-1.cm-1,钼(Ⅵ)含量在0~10μg/25mL范围内符合比尔定律。该方法直接用于豆类中痕量钼(Ⅵ)的测定,获得满意的结果。  相似文献   

10.
蒋华江  叶巧云 《化学世界》2001,42(11):579-581
合成了 1 - ( 2 ,3,5 -三氮唑偶氮 ) - 2 -萘酚 (简称 TZAN) ,研究了它与镍的显色反应。结果表明 :在 p H7.0~ 8.0的水溶液中镍与 TZAN形成一种稳定的红色配合物 ,其最大吸收波长位于5 2 8.8nm处 ,表观摩尔吸光系数ε=3.40× 1 0 4 L /mol· cm,配合物的组成 Ni2 + ∶ TZAN=1∶ 2。镍浓度在 0~ 1 .2 mg/L范围内服从比尔定律。在氟化铵和硫脲的存在下 ,可直接测定合金中的微量镍  相似文献   

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12.
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.  相似文献   

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14.
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.  相似文献   

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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.  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

20.
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。  相似文献   

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