甲醇-水流动相HPLC测定银杏萜内酯方法优化

优化了甲醇-水流动相HPLC测定银杏萜内酯的方法,建立了线性回归方程,并与药典正丙醇-四氢呋喃-水流动相方法进行比较。在此基础上,用两种方法对银杏叶、银杏外种皮、白果以及银杏叶提取物(EGB)样品中的萜内酯含量进行了对照分析。结果表明,甲醇-水梯度洗脱基线噪音小,柱效高,分离时间短。优化的洗脱条件为:甲醇-水为流动相,0～2 min,0～20%甲醇; 2～32 min,20%～60%甲醇,建立的方法在50～2 000 mg/L的浓度范围内具有良好的线性关系,检出限为0. 05～0. 09μg,不同浓度水平的加标回收率为92. 4%～101. 6%,相对标准偏差(RSD)值为2. 7%～5. 1%。两种方法测定银杏萜内酯没有明显差别,其中测定银杏叶中白果内酯、银杏内酯C、银杏内酯A、银杏内酯B的相对误差分别为0. 86、4. 2、1. 7、3. 9。     

分光光度法测定银杏萜内酯的含量

在弱碱性条件下,银杏萜内酯与Fe(Ⅲ)形成萜内酯-羟肟酸铁紫色环状配合物,最大吸收峰位于514nm处,分光光度法测定萜内酯含量在45~450μg/mL范围内服从比耳定律,标准曲线的回归方程为A=1.9316C 0.0129,相关系数r=0.9994,测定结果与HPLC法对比实验一致。方法简便、快速,可用于银杏样品中萜内酯含量的测定。     

银杏萜内酯提取分离工艺研究

银杏内酯A、B、C及白果内酯(文中简称GA、GB、GC和BB)分子极性依次增强。因此,不同极性的有机溶剂对4种银杏萜内酯有不同的选择溶解性。通过丙酮,乙酸乙酯与乙醇三级溶解并为每一级溶解液匹配合适的柱层析吸附剂与洗脱液,从银杏提取物中分离纯化极有药用价值的银杏萜内酯。结果表明,本方法可将银杏内酯的纯度由6%提高至80%以上,并可将它们逐一分离。     

高纯银杏萜内酯的超临界CO2提取研究

本文在分析银杏萜内酯重要的药效价值和广阔市场前景的基础上 ,将超临界 CO2 提取工艺与传统的有机溶剂提取法进行比较 ,结果发现超临界 CO2 法提取高纯银杏萜内酯是经济、合理的     

银杏叶中四种银杏内酯的含量测定

建立HPLC-ELSD法测定了30批银杏叶中4种银杏内酯的含量,并对所得数据进行分析研究.色谱条件为:phenonoonon C18色谱柱(250 mm×4.6 mm,5 μm),35%(体积分数)甲醇为流动相,1.000 mL/min的流速,ELSD检测器漂移管温度为60 ℃,氮气压力为1.72×105 Pa.得出红土栽培,未嫁接,树龄6～7 a的银杏叶中银杏内酯含量较高;4种银杏内酯总量集中在0.3%～0.5%(质量分数).该方法准确,重现性好,适用于银杏叶中4种银杏内酯的含量测定;银杏内酯的含量受生长环境影响差别较大,影响因素有待深入研究.     

双相深共熔溶剂提取的银杏果外种皮生物活性成分的分离回收

用双相深共熔溶剂（TP-DES）体系同时提取分离银杏果外种皮中亲水性成分萜内酯、黄酮、原花青素和疏水性成分银杏酚酸，分别利用EOPO（环氧乙烷-环氧丙烷共聚物）和大孔树脂对TP-DES中的亲水性和疏水性活性成分进行回收。萜内酯、黄酮和原花青素用分光光度法测定，银杏酚酸用HPLC测定，并根据回收过程中每一步的活性成分含量计算回收率。相对分子质量（简称分子量）为2650，质量分数为90%的EOPO进行回收萜内酯、黄酮和原花青素的回收率分别可达89.44%、53.27%和29.77%； HYA502B树脂静态吸附-解吸回收银杏酚酸回收率可达93.33%。     

HPLC-ELSD法测定银杏内酯B脂微球中银杏内酯B的含量

建立了银杏内酯B脂微球中银杏内酯B的含量测定方法。采用HPLC法,色谱柱为C18柱(250mm×4.6mm,5μm),流动相为甲醇-四氢呋喃-水(25∶10∶65),流速为1.0mL·min-1,柱温为30℃,蒸发光散射检测器,载气压力为4.0bar,漂移管温度40℃。结果银杏内酯B在80.91～269.70μg·m L-1时,线性关系良好(r=0.9998),平均加样回收率为100.25%,RSD为1.44%。该法准确,重现性好,可用于银杏内酯B脂微球中银杏内酯B的含量测定。     

HPLC-ELSD法测定银杏洋参胶囊中萜类内酯的含量

目的:建立银杏洋参胶囊中萜类内酯HPLC-ELSD定量测定方法。方法:色谱柱:SunfireTMC18柱(4.6 mm×150 mm,5μm);流动相:甲醇-水(30﹕70);流速:1.0 m L·min-1;柱温:35℃,漂移管温度:110℃,气体流速:2.9L·min-1。结果:白果内酯、银杏内酯A、银杏内酯B和银杏内酯C分别在0.9333~7.778μg(r=0.9994)、0.9846~8.205μg(r=0.9991)、0.9144~7.620μg(r=0.9992)和0.3027~2.5225μg(r=0.9991)进样量范围内线性关系良好,方法平均加样回收率分别为103.12%(RSD为1.81)、101.30%(RSD为2.93)、104.08%(RSD为4.41)和101.75%(RSD为1.00)。结论:本方法快速、准确,可用于同时检测银杏洋参胶囊中的萜类内酯,可作为该产品质量控制的方法。     

银杏内酯药代动力学及其剂型的研究进展

银杏内酯是银杏叶的重要活性成分,主要包括银杏内酯A、B、C和白果内酯等,具有调节血压和拮抗血小板活化因子等多种药理作用。本文总结分析了近年来有关银杏内酯药代动力学的研究,主要包括银杏内酯在体内吸收、分布、代谢和排泄的过程。为了提高其生物利用度和药效,现研究者采用多种新剂型、新技术制备银杏内酯制剂。文中归纳总结了银杏内酯制剂的制备和特点,旨在为提高银杏内酯生物利用度的研究提供参考。     

不同提取溶剂对银杏叶药材中多种成分含量的影响

目的 :研究水、40%乙醇、50%乙醇、60%乙醇、70%乙醇五种提取溶剂对银杏叶药材中总黄酮醇苷、萜类内脂及总银杏酸含量的影响,为银杏叶的合理使用提供依据。方法:HPLC条件:总黄酮醇苷检测采用Shim-pack C18色谱柱(150mm×4.6mm,5μm),甲醇-0.4%磷酸溶液(50:50)为流动相,检测波长为360nm;萜类内脂检测采用Agilent ZORBAX SB-C18色谱柱(250mm×4.6mm,5μm),甲醇-四氢呋喃-水(25:10:65)为流动相,蒸发光散射检测器,漂移管温度105℃,载气流速2.8L/min;总银杏酸检测采用Shim-pack C18色谱柱(150mm×4.6mm,5μm),甲醇-1%冰醋酸溶液(90:10)为流动相,检测波长为310nm。结果:槲皮素、山奈素、异鼠李素分别在0.0576~0.576μg、0.05672~0.5672μg、0.04128~0.4128μg范围内,进样量与峰面积呈良好的线性关系;银杏内酯A、银杏内酯B、银杏内酯C、白果内酯分别在2.442~20.35μg、2.109~17.575μg、1.803~15.025μg、1.992~16.60μg范围内,进样量的对数与峰面积的对数呈良好线性关系;白果新酸在0.2008~2.008μg范围内,进样量与峰面积呈良好的线性关系;水、40%乙醇、50%乙醇、60%乙醇、70%乙醇回流提取制备的供试品溶液中总黄酮醇苷的含量分别为2.06,2.85,3.20,3.50,2.97 mg/20m L;萜类内脂的含量分别为0,1.04,1.25,1.57,2.08 mg/20m L;总银杏酸的含量分别为0,7.95,10.20,11.61,12.13 mg/20m L。结论:不同提取溶剂制备的供试品溶液中三种成分的含量差别很大,民间以泡茶的方式服用银杏叶是合理的,切不可泡酒服用。     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。