超声提取-高效液相色谱法测定烟草中烟碱含量

确定了制备烟碱分析样品的超声波提取条件:0.4% NaOH溶液为溶剂、液固比40:1(Ml:g)、提取时间4 h.采用高效液相色谱法检测烟碱含量,平均加样回收率为98.8 %,相对标准偏差为1.2%.结果表明超声提取-高效液相色谱法测定烟草中烟碱含量准确度高、速度快.     

反相高效液相色谱法测定化妆品中鞣花酸

采用反相高效液相色谱法测定化妆品中鞣花酸的含量.色谱条件为:Venusil XBP-C18(4.6 mill i.d×250 mm,5 μm)色谱柱,流动相V(乙腈):V(水):V(三氟乙酸)=20:80:0.08,流速1.0 mL/min,检测波长254 nm.结果表明,在此条件下鞣花酸在3.98 μg·mL-1～79.6 μg·mL-1范围内与相应的峰面积具有良好的线性关系(R2=0.999 8),线性回归方程为A=203.83p-2.462 7,回收率在96.5%～101.5%,RSD为0.6%.     

HPLC法测定槐米中槲皮素成分的微波辅助提取

目的 建立高效液相色谱法测定槐米中槲皮素的含量.方法 用正交试验法确定微波辅助提取的最优条件,采用Diamonsil C18柱(200mm×4.6mm,5 μm),以甲醇-0.4%磷酸溶液(70∶30)为流动相,流速0.8mL·min-1,检测波长370nm.结果 线性范围(8.92～89.2)μ g·mL-1,r=0.9991,加样回收率98.59%(RSD为2.26%).结论 本方法简便、准确,所得结果稳定、重复性好,可作为槐米药材质量控制的定量方法.     

RP-HPLC法测定依普利酮片的含量及有关物质

目的:建立反相高效液相色谱法测定依普利酮片含量及有关物质的方法.方法:色谱柱为迪马 C18(150 mm×4.6 mm,5 μm)色谱柱,流动相为乙腈-水(30:70),流速为 1.0 mL·min-1 检测波长为 252 nm.结果:在该条件下,依普利酮与有关物质分离良好,依普利酮浓度在在 49.824～498.24...     

反相高效液相色谱法测定化妆品中羟基喹啉

采用反相高效液相色谱法测定化妆品中羟基喹啉的含量.色谱条件为:Kromasil C18色谱柱(250 mm×4.6 mm i.d.,5μm),流动相为V(甲醇):V(0.01 mol/L癸烷磺酸钠溶液(磷酸调pH=2.25))=62:38的混合溶液,流速1.0 mL/min,检测波长240 nm,柱温25℃,进样量20μL.结果表明,该方法的检出限为2.254 μg/g,线性范围为1.0～100.0μg/mL,回收率为95.5％～100.1％,RSD为0.07％～2.18％.     

高效液相色谱法测定IIR中防老剂BHA和BHT含量

采用高效液相色谱法 (HPLC)测定IIR中防老剂BHA和BHT的含量。确定测定条件为 :流动相　甲醇 /水(体积比为 90 /10 ) ;流速　 1.0mL·min- 1 ;检测波长　 2 45nm ;柱温　 2 5～ 3 0℃ ;进样量　 10 μL。防老剂BHA和BHT测定的变异系数分别为 1 2 2 %和 1 3 7% ,回收率大于 96%。     

高效液相色谱法测定八正泡腾片中大黄素的含量

目的建立八正泡腾片质量标准的含量测定项目。方法采用高效液相色谱法测定八正泡腾片中大黄素的含量,色谱柱为Dikma C18(250mm×4.6mm,5μm),流动相为甲醇-0.1%磷酸溶液(85:15),检测波长为290nm,流速为1mL·min-1,柱温为40℃。结果大黄素的线性范围为0.04992～0.3328μg(r=0.9999),平均回收率为100.88%(n=6,RSD=2.02%)。结论高效液相色谱法简便、准确,可以有效控制八正泡腾片的质量。     

R-HPLC法测定鬼臼毒素软膏含量和有关物质的研究

目的:采用反相高效液相色谱法测定鬼臼毒素软膏的含量及其有关物质。方法:采用ODS C18色谱柱(5μm,4.6mm×200mm),以甲醇-水(55∶45)为流动相,流速1.0mL·min-1,检测波长292nm。结果:反相高效液相色谱法测定的线性范围为0.303~0.707mg/mL,相关系数r=0.9998;三种不同浓度供试液精密度分别为1.05%(n=5)、0.87%(n=5)、1.16%(n=5)。结论:采用反相高效液相色谱法测定鬼臼毒素软膏的含量及有关物质,方法简便、快速、准确、专属性好。     

HP LC法测定原料药磷酸芦可替尼的含量和有关物质

采用高效液相色谱法测定原料药磷酸芦可替尼的有关物质。以十八烷基硅烷键合硅胶柱(Inertsil ODS-3 250 L×4.6 mm,5μm)为色谱柱,甲醇:水=60:40为流动相,梯度洗脱,流速1.0 mL·min~(-1),检测波长为220 nm。结果表明,高效液相色谱法测定磷酸芦可替尼线性范围为0.518～5.175μg/mL,检测限为0.207μg/mL,定量限为0.518μg/mL,精密度(RSD=0.96%)良好,各杂质平均回收率均在90%～110%之间。高效液相色谱法测定磷酸芦可替尼的有关物质准确、有效、灵敏度高。     

烟酰胺和3-氰基吡啶的HPLC检测

采用高效液相色谱法测定烟酰胺和3-氰基吡啶的含量.色谱条件为:STR-ODSⅡ柱(4.6 mm×150 mm),流动相为甲醇∶水=1 ∶ 3,流速1.000 mL·min-1,检测波长254 nm,柱温30℃.该方法的烟酰胺和3-氰基吡啶检测范围均为1.0～40.0 mg·L-1,烟酰胺的检测限为0.25 mg·L-1...     

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.     

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.     

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。