HPLC法测定3-氨基-4-氯苯甲酸的含量

建立用HPLC法测定 3-氨基 - 4 -氯苯甲酸的含量 ,采用KromasilC18柱 ,以甲醇 - 0 .0 5 % (φ)磷酸水溶液 (体积比 6 5 :35 )为流动相 ,流速 1.2mL·min-1,线性范围 0 .0 8～ 0 .4 0× 10 -4g·L-1,相关系数r=0 .9999,加标回收率为 10 1% ,RSD为 0 .98% (n =6 )。该法操作简便、准确。     

超高效液相色谱-串联质谱法测定无糖食品中木糖的含量

以自制的13C-木糖为内标,建立了无糖食品中木糖的高效液相色谱-串联四级杆质谱联用测定法。以Phenomenex Lichrosorb 5色谱柱(250mm×4.6mm,5μm)为分离柱,乙腈-水(V/V=80∶20)为流动相,以水提取样品,在电喷雾正离子选择反应检测模式下进行定性定量分析。该方法的检出限为10ng/mL,线性范围为10～1000ng/mL,加标回收率为96.09%～99.90%,相对平均偏差(n=5)为1.2%～2.5%。     

毒·唑磷乳油的气相色谱分析

采用 5 %OV -10 1/GasChromQ(15 0～ 180 μm)色谱柱 ,邻苯二甲酸二戊酯为内标物 ,对毒·唑磷乳油有效成分毒死蜱、三唑磷含量进行气相色谱分析 ,毒死蜱、三唑磷变异系数分别为 1.6 3 %和 0 .6 7% ,线性相关系数分别为 0 .990 7和 1.0 0 6 9;回收率分别为 99.1%～ 10 0 .1%和 99.6 %～ 99.7%。     

高效液相色谱快速测定茶叶中儿茶素的含量

分析了酸的种类及 pH对高效液相色谱 (HPLC)法测定表儿茶素 (EC)、表没食子儿茶素没食子酸酯(EGCG)、表儿茶素没食子酸酯 (ECG)、表没食子儿茶素 (EGC)、儿茶素 (C)和咖啡因的影响 ,实验表明 :酸尤其是乙酸不仅能改善各组分的峰形 ,而且对保留时间和出峰顺序均有较大的影响。确定了简单、快速分析 5种儿茶素及咖啡因的高效液相色谱分析方法。采用C18反相柱 ,水 -甲醇 -乙酸 ( 73. 0 / 2 3. 0 / 2 . 0 )为流动相 ,在流速为 1. 0mL·min-1,柱温 30℃ ,检测波长 2 80nm时等度洗脱分析样品 ,分析时间仅为 2 5min ,线性范围为 0 . 8～ 90mg·mL-1(r =0 998～ 0 999) ,回收率为 98. 2 %～ 10 0 . 3%,检测限为 5～ 10ng。     

高效液相色谱法分析甲基丙烯酰氧乙基三甲基氯化铵中的阻聚剂

利用反相高效液相色谱法 (HPLC) ,采用ExtendC18柱、以甲醇 -水 ( 0 .0 5 %高氯酸 )为流动相 (体积比为 5 5 :45 ) ,二极管阵列检测器对甲基丙烯酰氧乙基三甲基氯化铵 (简称DMC)中的阻聚剂对羟基苯甲醚进行了检测。试验结果证明 ,对羟基苯甲醚在0 .0 2mg/mL～ 2mg/mL浓度范围内与峰面积呈良好的线性关系。方法回收率为 98.9%～ 10 1.6% ,相对标准偏差为 1.3 2 % ,最低检测限为 5× 10 - 4mg/mL。     

高效液相色谱法测定20%高效氯氰菊酯·胺菊酯乳油中氯氰菊酯和胺菊酯的含量

采用高效液相色谱法 ,使用正相色谱柱 (ZORBAXRX SIL)和紫外检测器 ( 2 40nm)同时测定高效氯氰菊酯和胺菊酯。流动相为正己烷 +乙酸乙酯 ( 93+7) ,该方法的标准偏差为 0 .0 7%和 0 .0 9% ,变异系数为0 .69%和 0 .9% ,回收率为 99.1%～ 10 1.3%和 99.7%～ 10 1.2 %。     

液相色谱-串联质谱测定豆芽中4种四环素类药物残留量研究

建立了液相色谱-串联质谱法测定豆芽中金霉素、土霉素、四环素和强力霉素4种四环素类抗生素残留量的方法。样品用0. 1 mol/L EDTA-Mellvaine缓冲液超声提取,HLB柱净化,C_(18)色谱柱分离,正模式下检测。4种四环素类抗生素在5～200μg/L范围内线性关系良好;方法定量限(S/N=10)为1. 5～6. 0μg/kg;添加水平为5、10、20μg/kg时,平均回收率在70. 2%～93. 3%之间;相对标准偏差(RSD,n=6)为8. 5%～13. 7%。方法简单快速,灵敏度高,成功应用于市场上绿豆芽和黄豆芽的检测。     

微乳色谱法同时测定化妆水中9种防腐剂

建立同时测定化妆水中9种防腐剂的微乳色谱方法。化妆水样品经甲醇溶解、超声提取后,经0. 22μm微孔滤膜过滤,色谱柱为Diamonsil C18柱(250 mm×4. 6 mm,5μm),以3. 0%(W/V)十二烷基硫酸钠(SDS)-6. 0%(V/V)正丁醇-0. 4%(V/V)正辛烷-90. 6%(V/V) 0. 1%磷酸水为流动相,柱温为30℃,检测波长254 nm,流速0. 7 m L/min,标准曲线法定量。9种防腐剂在19 min内彼此完全分离,在0. 945～4999. 2μg/m L的范围内线性关系良好,相关系数r0. 9996,平均回收率为95. 1%～104. 6%,RSD为0. 57%～3. 30%。该方法绿色环保、简单灵敏、准确快速,可用于化妆水中多种防腐剂的同时测定。     

HPLC测定养血当归软胶囊中阿魏酸的含量

目的测定养血当归软胶囊中阿魏酸的含量。方法利用HPLC法,采用Diamonsil(钻石) C_(18)(150mm×4. 6mm,5μm)色谱柱,流动相为甲醇一乙腈一0. 1%磷酸溶液(10:10:89),流速:1. 0 mL·min~(-1),柱温:30℃,检测波长:317nm。结果阿魏酸在0. 13～1. 04μg. mL~(-1)之间线性良好。养血当归软胶囊中阿魏酸的平均回收率为100. 4%,RSD为1. 08%。结论 HPLC测定养血当归软胶囊中阿魏酸的含量,方法简便,样品处理方便易行,可作为养血当归胶囊的质量控制方法。     

HILIC-MS/MS测定牛奶中4种含氮化合物的含量

建立同时检测三聚氰胺、三聚氰酸、尿酸、二氰二胺含量的高效液相-质谱联用方法。采用亲水色谱-串联质谱方法,色谱柱为Agilent Hilic柱(4. 6 mm×100 mm,3. 5μm),以乙腈-水(1∶1)为流动相进行恒度洗脱,流速为1 m L/min,进样量10μL,柱温为25℃。结果三聚氰胺在浓度范围0. 5～20 ng/m L、三聚氰酸、二氰二胺、尿酸的浓度范围均在100～4000 ng/m L内线性关系良好(R≤0. 9986),加样回收率均在82. 5%～115. 0%之间。本方法简便、快速、灵敏度高,适于同时测定牛奶中三聚氰胺、二氰二胺、三聚氰酸、尿酸的含量。     

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.     

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。     

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.     

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。     

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.