褪色光度法测定硫酸庆大霉素的研究

基于偶氮蓝与硫酸庆大霉素相互作用而导致溶液吸收光谱的变化,用褪色光度法对该体系进行了研究。在pH=4.10的缓冲溶液中,偶氮蓝在553 nm波长处有一强的特征吸收峰,当在其溶液中加入硫酸庆大霉素后,溶液发生褪色反应,553 nm处吸收强度降低,吸光度差值与硫酸庆大霉素质量浓度成正比。最佳条件下,硫酸庆大霉素的质量浓度在0.1~3.2 mg.L-1范围内遵守比尔定律,表观摩尔吸光系数ε=6.8×104L.mol-1.cm-1,检测限(3σ)为0.087 mg.L-1。方法用于硫酸庆大霉素注射液的测定,回收率为97.2%~100.2%。     

曙红Y共振光散射法测定水中十六烷基三甲基溴化铵

利用共振光散射(RLS)技术,通过曙红Y与阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)缔合产生强烈共振光散射增强效应,建立了一种测定阳离子表面活性剂CTAB的方法.实验结果表明,在pH=4.96的柠檬酸钠-盐酸缓冲介质中,采用吐温80作为曙红Y -CTAB体系的稳定剂,痕量CTAB的加入导致曙红Y在440～ 600 nm波长内的共振光强度增加,最大RLS峰位于538 nm处,其强度与CTAB的质量浓度在0～40 mg·L-1内成正比,检出限为0.012 mg·L-1.方法具有较高的灵敏度和良好的选择性,可用于水样中CTAB的测定.     

有机染料对DLP型3D打印光敏树脂的影响研究

在数字光处理技术(DLP)型3D打印机所使用的光敏树脂中,染料不仅可以控制颜色,同时还影响打印速度和打印精度。系统考察了在405 nm处有光吸收性能的5种有机染料(柠檬黄、苏丹红Ⅲ、姜黄素、栀子蓝、曙红Y)的紫外-可见吸收性能和光稳定性,以及在405 nm波长LED光源3D打印光敏树脂中的引发活性及增感活性。结果表明,在405 nm处的吸收强弱顺序为姜黄素苏丹红Ⅲ栀子蓝曙红Y≈柠檬黄;姜黄素和曙红Y在溶液中具有光不稳定性,在405 nm处吸收随着光照时间的延长逐渐降低,而栀子蓝、苏丹红Ⅲ和柠檬黄表现出良好的光稳定性。光引发活性检测结果表明,姜黄素、栀子蓝和曙红Y本身具有自由基光引发活性,曙红Y的光引发活性最高;以光引发剂二甲苯碘盐为例,考察了染料对碘盐的增感作用,结果发现曙红Y、栀子蓝和姜黄素与碘盐组成的光敏引发体系在405 nm波长LED光源下表现出高效的光引发活性。     

一种光度法测定双组分染料浓度的方法研究

采用光度法测定了含有曙红和桃红的混合染料的吸光度,并用最小二乘法计算两种染料的浓度。用分光光度计测定曙红和桃红的最大吸收峰,然后确定不同浓度的曙红溶液和桃红溶液的吸光度,绘制标准曲线并进行拟合,得到拟合方程。最后测定含曙红和桃红的混合染料的吸光度,由回归系数最小二乘估计法得到最大吸收波长处的吸光度-浓度方程,计算出两种染料的浓度,回收率在98%¹02%之间。该法具有快速、简捷实用等特点。{A514.5合成样=(1.097×10-1c曙红-7.000×10-4)+(4.860×10-2c桃红-2.200×10-3)A534合成样=(2.790×10-2c曙红+6.000×10-4)+(9.320×10-2c桃红+4.900×10-3)     

B-藻红蛋白在表面活性剂中的光谱性质

对标题化合物在3种不同类型的表面活性剂中的可见吸收光谱进行了研究.实验条件下,阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)使B-藻红蛋白的最大吸收峰由545 nm蓝移至506 nm,随CTAB浓度增加,最大吸收值显著下降.阴离子表面活性剂十二烷基硫酸钠(SDS)在低浓度时对B-藻红蛋白的特征吸收峰形影响不大,当SDS的浓度2.0×10-3mol/L时,B-PE在564 nm的吸收峰消失.非离子表面活性剂Triton X-100对B-藻红蛋白的吸收峰形没有产生明显影响,并使吸收峰强度均有所增加.还初步探讨了B-藻红蛋白在3种表面活性剂中光谱变化的机理.     

荷移-紫外分光光度法测定硫酸庆大霉素含量

利用硫酸庆大霉素与四氯苯醌在水溶液中发生电荷转移反应,建立了简单快速测定硫酸庆大霉素含量的荷移紫外分光光度法。荷移络合物在波长342 nm处有最大吸收,该荷移衍生物的吸光度与硫酸庆大霉素浓度在0.1~3 mg/m 范围内吸光度和浓度呈现良好线性关系y=0.1652x+0.3054,R~2=0.9996,平均加样回收率为100.81%,RSD为2.55%。该方法简便、准确、重现性好,适用于硫酸庆大霉素的快速测定。     

番红花红分光光度法测定硫酸皮肤素

研究了硫酸皮肤素对番红花红染料发生缔合反应的条件,分光光度特征和分析化学性质.结果表明:在pH 5.8的BR缓冲溶液中,硫酸皮肤素与番红花红形成离子缔合物时,染料发生明显的退色反应,最大退色波长位于552 nm处.体系吸光度的降低与硫酸皮肤素的浓度成正比,硫酸皮肤素浓度在0.09～3.0 μg/mL范围内符合比耳定律,摩尔吸光系数ε达1.02×106 L·mol-1·cm-1,相关系数r0.999,其检出限为0.029 μg/mL(3σ).研究了共存物质的影响,表明方法选择性好,用于猪皮提取液中硫酸皮肤素的测定,结果满意.     

硫酸耐尔蓝褪色光度法测定十二烷基苯磺酸钠

基于硫酸耐尔蓝与十二烷基苯磺酸钠相互作用而导致溶液吸收光谱的变化,用褪色光度法对该体系进行了研究,在pH=4.80缓冲溶液中,硫酸耐尔蓝在595 nm处有一强的特征吸收峰,当在其溶液中加入十二烷基苯磺酸钠后,溶液发生褪色反应,吸光度差值与十二烷基苯磺酸钠浓度成正比。最佳条件下,十二烷基苯磺酸钠浓度在0.5～5 mg/L范围内符合比尔定律,检出限(3σ)为0.16 mg/L。方法用于环境水中十二烷基苯磺酸钠的测定,回收率在98.8%～102.2%。     

曙红Y分光光度法测定季铵盐消毒剂的含量分析方法研究

建立了一种紫外-可见分光光度法测定消毒剂中季铵盐含量的方法。用水溶性曙红Y与季铵盐进行显色反应,使用紫外-可见分光光度计测量其在545 nm处的吸光度。结果表明,季铵盐类消毒剂的线性范围为0. 5~5. 0 mg/L,相关系数均大于0. 999,相对标准偏差小于5%,回收率在97. 0%~107. 5%之间,该方法快速、准确,适用于消毒剂中季铵盐含量的测定。     

茜素红共振散射法测定硫酸庆大霉素

在pH5.5的Britton-Robinson介质中,茜素红和硫酸庆大霉素(GEN)相互作用形成缔合物,使体系的共振散射信号(RLS)增强,最大散射峰位于312 nm处,且增强的RLS强度与GEN浓度成正比,据此建立了一种测定硫酸庆大霉素含量的新方法。测定硫酸庆大霉素的线性范围是0.15~1.5 U/mL,检出限为0.029 U/mL。将方法用于硫酸庆大霉素注射液中硫酸庆大霉素含量的测定,结果满意。     

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。