加替沙星对映异构体拆分研究

目的 建立加替沙星对映异构体手性拆分的方法.方法 采用Chiral CD-Ph手性色谱柱(4.6mm×250mm,5μm),考察了不同条件对分离的影响.结果 以0.5mol·L-1 NaClO4溶液(pH值4.0)-甲醇(53∶47)为流动相时,加替沙星两个对映异构体分离度最佳,分离度为1.6.线性关系、精密度和重复性...     

柱色谱法纯化马铃薯叶中的茄尼醇

通过柱色谱法从马铃薯叶的提取物中分离提纯了茄尼醇,并以RP-HPLC法测定了茄尼醇的质量分数。采用硅胶对茄尼醇进行吸附纯化,以茄尼醇的实测收率、质量分数为考察指标,通过对硅胶颗粒、洗脱剂流速、洗脱剂组分配比进行考察,确定了茄尼醇的柱色谱优化条件。结果表明,以200~300目硅胶为填料,流动相流速为2.0 mL/m in,洗脱剂以石油醚、V(石油醚)∶V(乙酸乙酯)=20∶1、15∶1、9∶1进行梯度洗脱,茄尼醇的质量分数达到85.37%,重结晶后达到97.47%。     

超临界流体色谱纯化Z-藁本内酯的研究

将超临界流体色谱技术应用于当归挥发油中Z-藁本内酯的提纯。采用ZorBax SB-C18色谱柱(250 mm×9.4 mm I.D.,5μm),分别考察了改性剂、流速、压力、温度对色谱分离过程的影响,确定了较适宜的色谱提纯条件:CO2流速10 g·min-1,柱温313.15 K,柱压14 MPa;在此工艺条件下提纯制备Z-藁本内酯单体,得到的产品纯度为98.5%(wt)。研究了色谱过程的热力学规律,绘制色谱分离过程的van’t Hoff曲线,并由此得到了色谱相转移过程焓变为21.46kJ·mol-1,并比较了Z-藁本内酯与相邻组分从流动相到固定相分配过程中焓变和熵变的差值,在此条件下Z-藁本内酯色谱分离过程为焓控过程。     

正相液相制备色谱分离纯化三七叶甙中人参皂甙单体Rb3

以三七叶甙粗提物为原料,采用大孔吸附树脂法和正相液相制备色谱法建立了分离纯化三七叶甙中人参皂甙单体Rb3的制备工艺.首先采用D-101B大孔吸附树脂对原料进行精制,得到Rb3含量为50%的三七叶甙精制物.进而通过正相液相制备色谱柱(φ80mm×1000mm)分离纯化三七叶甙精制物,通过考察流动相组成、流速和上样量等因素对分离效果的影响,确定了适宜的工艺操作条件流动相为正丁醇-乙酸乙酯-水溶液[体积比为211(上层)],流速为35～40mL.min-1,上样量为10g.在该工艺条件下得到了人参皂甙单体Rb3,纯度达95%.本方法简便、分离效率高、重复性好,为人参皂甙类新药的开发奠定了基础.     

超临界CO_2流体色谱分离2,4-二叔丁基酚和2,6-二叔丁基酚

采用超临界CO_2流体色谱分离酚类同分异构体化合物:2,4-二叔丁基酚和2,6-二叔丁基酚。通过单因素法考察了色谱柱类型、改性剂种类、改性剂浓度、色谱柱温、背压对容量因子和分离度的影响,确定了较佳的分离条件:色谱柱Sepax SFC-Pyridine(250 mm×4.6 mm,I.D.5μm);流动相:V(CO_2):V(乙醇)=90:10;流速:3 m L/min;柱温:35℃;背压:100bar;紫外检测波长:270 nm;进样量:30μL浓度为1.0 mg/m L的2,4-二叔丁基酚和2,6-二叔丁基酚的甲醇溶液,此时,分离时间在5 min以内,分离度达到4.68。     

反相制备液相色谱分离纯化辣椒碱单体

用反相制备液相色谱法从辣椒碱类化合物中分离得到了高纯度辣椒碱单体.采用碳十八硅胶(ODS)柱(200 mm×10.0 mm),考察了流动相组成、进样浓度、进样体积和流动相流速等对分离的影响,确定了适宜的工艺操作条件:流动相为甲醇/水(75/25,v/v),进样浓度为180 mg·mL-1,进样体积为2.08 mL,流速为4.0 mL·min-1.在该工艺条件下,得到的辣椒碱单体纯度为95.23%,回收率为93.27%,产率为4.38 g·L-1·h-1,流动相消耗为0.087 L·g-1.本工艺操作简便,分离效率高,产品质量好,为辣椒碱单体的制备研究提供了一种新的方法.     

杀螟松的反相液相色谱分析

高效液相色谱通常调节流动相的组成和柱温来改变色谱分离情况。本文对于反相键合相液相色谱,详细测定了流动相组成、柱温分别对农药杀螟松及其杂质的容量因子、分离因子、理论塔板数和分离度等全面的影响,并测定了有关的热力学参数,为选择色谱操作条件提供实验根据。一、实验 (一)仪器及实验条件仪器:美国Varian公司生产的VISTA56型液相色谱仪     

泽兰化学成分反相高效液相色谱分离条件的优化

优化了泽兰V(乙醇)∶V(水)=70∶30提取物的分离条件。采用反相高效液相色谱法(RP-HPLC)考察了不同波长、酸抑制剂类型及其浓度、流动相梯度、进样量以及柱温对其分离效果的影响。确定其分离条件如下:Hypersil ODS2色谱柱(5μm,4.6 mm i.d.×250 mm);流速1.0 mL/m in;检测波长280 nm;流动相:(A)(甲酸)=0.75%的水溶液(以下简称为X%Y-水,其中X为数字,Y为水中的添加剂),(B)乙腈;梯度洗脱条件为:φ(B)=10%(5 m in)65 m inφ(B)=55%;进样量为20μL;柱温30℃。该方法获得的色谱图基线较平稳,分离度较高,能有效地对泽兰化学成分进行分析,可用于泽兰的质量控制。     

分子蒸馏技术提纯茄尼醇的工艺研究

分子蒸馏技术是一种在高真空条件下进行的连续蒸馏过程,适合于分离高沸点、高粘性、热敏性及具有生物活性的混合物.应用刮膜式分子蒸馏装置对茄尼醇的提纯进行了研究,实验过程中茄尼酵粗品不需要进行脱色等方法预处理,通过两次分子蒸馏,即可得到高纯度茄尼醇.考察了多种分离工艺参数对茄尼醇纯度和收率的影响.得到了用分子蒸馏技术提纯茄尼醇的最佳工艺条件:进料速度350-400 mL·h-1,进料温度100℃,蒸馏温度为200～220℃,蒸发压力为10 Pa,刮膜器转速300～400 r·min-1,最终产品纯度和收率分别达到97.6%和 77.1%,达到了用分子蒸馏分离茄尼醇的目的,说明采用分子蒸馏设备提纯茄尼醇粗品是可行的.     

梯度反相高效液相色谱法测定头孢西丁钠中的有关物质

采用PHenomenex-PHenyl色谱柱(250 mm×4.6 mm,4 μm);以水(用甲酸调pH至2.7)为流动相A,乙腈为流动相B,进行梯度洗脱;流速1.2 mL/min;紫外检测波长235 nm.本方法灵敏,准确,分离度良好,可用于头孢西丁钠中头孢西丁与未知杂质的检测.     

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.     

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。     

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.