反相高效液相色谱法分析化妆品用白色茶多酚

采用反相高效液相色谱法测定化妆品用白色茶多酚中的多种活性成分。色谱柱:HypersilBDSC184 6×200mm;流动相:梯度洗脱,A相为0 5%HAc水溶液与乙腈体积比为95∶5,B相为甲醇与乙腈与0 5%醋酸水溶液体积比为50∶30∶20;流速为0 8mL/min;检测波长为280nm。结果表明:该方法能同时测定儿茶素没食子酸酯、表没食子儿茶素、右旋儿茶素、表没食子儿茶素没食子酸酯、表儿茶素、没食子儿茶素没食子酸酯、表儿茶素没食子酸酯和咖啡因,这8种组分的质量分数与峰面积有良好的线性关系(r=0 9982～0 9999),加样回收率为86 9%～106 6%(n=5)。     

茶多酚含量与儿茶素含量关系研究

研究了不同规格茶多酚产品中表没食子儿茶素(EGC)、儿茶素(DL-C)、表没食子儿茶素没食子酸酯(EGCG)、表儿茶素(EC)、没食子儿茶素没食子酸酯(GCG)、表儿茶素没食子酸酯(ECG)6种儿茶素含量及其总量与茶多酚含量的关系.结果发现,对于同种规格用同种原料和同种工艺生产的茶多酚产品,其茶多酚含量与6种儿茶素总量成一定的比例关系.茶多酚含量用酒石酸亚铁分光光度法测定,儿茶素含量用高效液相色谱法测定.     

高效液相色谱法分离纯化酯型儿茶素的研究

采用反相高效液相色谱技术 ,分离制备粗儿茶素粉末中表没食子儿茶素没食子酸酯( EGCG)、没食子儿茶素没食子酸酯 ( GCG)、表儿茶素没食子酸酯 ( ECG)三种酯型儿茶素馏分。制备色谱条件 :色谱柱 ,( 80 mm i.d× 5 0 0 mm,Fuji C18,粒径 2 5～ 40 μm) ;流动相 :有机醇 A- 1 /水( 1 6.5 /83.5 ,v/v,流速为 5 8m L/min;检测波长 2 78nm,进样量 30 0 0 mg。将所收集相应馏分分别经 P- 1大孔树脂吸附脱去溶剂 ,低沸点溶剂洗脱 ,旋转蒸发浓缩洗脱液 ,冷冻干燥后 ,得到 EGCG、GCG、ECG白色粉末。各物质经 HPLC检测纯度达 99.2 %以上。该法适用于分离纯化 EGCG、GCG、ECG三种酯型儿茶素单体     

普洱熟茶化学成分研究

从云南西双版纳大度岗茶厂生产的普洱熟茶中分离得到9个化合物,通过波谱分析分别鉴定为:咖啡因、芦丁、水杨酸、没食子酸、牡荆素、(+)-儿茶素、(-)-表儿茶素-3-O-没食子酸酯、(-)-表没食子儿茶素没食子酸酯、槲皮素。     

茶多酚生产应用与开发前景

茶多酚,简称TP。茶多酚是茶叶中的多酚类物质,主要由表儿茶素(L-EC)、表儿茶素没食子酸酯(L-ECG)、表没食子儿茶素(L-EGC)、表没食子儿茶素没食子酸酯(L-EGCG)等4种成分组成。茶多酚产品中儿茶素一般占60％～80％,此外,还含有没食子酸等酚酸类化合物、儿茶氧化物和缩聚产物及咖啡等生物碱类物质。 迄今,在众多的由茶叶及其副产品深加工而得的产品中,除速溶茶外,被人们研究和认识最为深刻和广泛的就是茶多酚了。茶多酚是     

茶多酚的经皮渗透特征及其对UVA致HSF氧化损伤的保护作用

研究了茶多酚的经皮渗透特征,探究茶多酚对长波紫外线（UVA）诱导的人皮肤成纤维细胞氧化损伤的保护作用机理。采用Franz扩散池,以大鼠皮肤为屏障,建立了完善的检测方法,用高效液相色谱检测茶多酚中儿茶素、表儿茶素、表儿茶素没食子酸酯、表没食子儿茶素没食子酸酯的经皮渗透指标;通过建立UVA损伤HSF细胞模型,探究了茶多酚对细胞活性氧含量、丙二醛水平、超氧化物歧化酶和谷胱甘肽过氧化物酶活力的影响。结果表明该检测方法具有较好的专属性、精密度和加样回收率,且茶多酚中的儿茶素、表儿茶素、表儿茶素没食子酸酯、表没食子儿茶素没食子酸酯4种物质均可较好地作用于皮肤,其中表儿茶素在透皮释放方面具有明显优势。茶多酚通过降低UVA辐照后HSF细胞中的ROS含量和MDA水平,可提高细胞内SOD和GSH-Px活力,对UVA诱导的HSF细胞氧化损伤具有良好的保护作用。     

茶多酚生产应用及开发前景

茶多酚，英文名Teanloyphenols，简称TP，茶多酚是茶叶中的多酚类物质，主要由表儿茶素（I。－EC）、表儿茶素没食子酸酯（I。一ECG）、表没食子儿茶素（L一EGC）、表投食子儿茶素投食子酸酯（I。一EGCG）等4种成分组成。在茶多酚产品中儿茶素一般占6O％～SO％，此外，还含有没食子酸多酚酸类化合物、儿茶素氧化物和缩聚产物及咖啡因等生物碱类物质。国内外对茶多酚的研究开发始于SO年代，到gO年代逐渐形成热点和高潮。最初茶多酚只是作为抗氧化剂来研究，但随着研究应用的深入，又发现茶多酸具有诸多生理活性和药理功能，并开拓…     

毛细管区带电泳法测定白沙绿茶汤中的咖啡因、茶氨酸、EC和EGCG

目的:以白沙绿茶为研究对象,探讨科学的泡茶方式.方法:利用毛细管电泳法,以含有20mmol/L硼砂和磷酸盐(pH9.5)为电泳介质,在电压25kV、柱温25℃条件下分离和210nm波长处检测,测定在不同条件下白沙绿茶汤中咖啡因、茶氨酸、表儿茶素(EC)和表没食子儿茶素没食子酸酯(EGCG)的浓度.结果:在白沙绿茶的取量为0.2g/10mL、泡茶温度为90℃、浸泡时间为60min且用纯净水泡茶的条件下,茶汤中的咖啡因、茶氨酸、EC和EGCG的浓度最高.结论:按4g白沙绿茶/200mL、90℃左右的纯净水浸泡60min,效果最佳.     

国外有关塑料助剂研究的期刊文摘

正聚L-乳酸/聚L-乳酸接枝马来酸酐/表没食子儿茶素没食子酸酯共混物制备抗菌食品包装膜[Journal of Plastic FilmSheeting,2017,33(1):10-34.]本研究检测了由聚(L-乳酸)/聚(L-乳酸)接枝马来酸酐共聚物和表没食子儿茶素没食子酸酯(EGCG)共混物制成的塑料膜的抗菌活性。通过直接接触法、固体和液体培养基方法检测了EGCG在掺入量为0.03,0.5,5和10wt%并作为天然抗菌剂时的抗菌效果。研究中针对两种细菌(革兰     

利用寡聚环糊精配基键合介质分离表没食子儿茶素没食子酸酯的新方法

研究了利用寡聚环糊精配基键合的高效凝胶介质分离纯化茶多酚中的表没食子儿茶素没食子酸酯的新方法。考察了不同种类的流动相对分离效果的影响。最终确定采用水／乙醇／乙腈为57／30／13（体积比）进行等梯度洗脱,一次色谱分离的收率和纯度分别为73％、98％,介质经过0．5mol／L的NaOH-水-30％乙酸简单再生后即可重复利用。     

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.