催化动力学光度法测定痕量钒(Ⅴ)的研究

研究了在 p H=4及没食子酸存在下 ,微量钒 ( )催化溴酸钾氧化邻苯二胺的动力学条件 ,建立了催化动力学光度法测定痕量钒 ( )的新方法。方法的测定范围为 0～ 0 .0 2 5 μg· 2 5 m L- 1 ,检出限为 1.18× 10 - 6 g·L- 1 ,相对标准偏差为 4 .6 3% (n=10 ) ,线性回归方程为△ A=2 5 .6 6 c(μg· 2 5 m L- 1 ) - 0 .0 15 7(r=0 .9997) ,表观摩尔吸光系数ε4 6 0 nm=3.2 7× 10 7L· m ol- 1 · cm- 1 。该法灵敏度高 ,选择性好 ,直接应用于水样和食品样中痕量钒( )的测定 ,结果满意     

RP-HPLC法测定天麻珍珠头痛胶囊中天麻素的含量

建立天麻珍珠头痛胶囊中天麻素的含量测定方法。采用反相高效液相色谱法测定天麻素含量,固定相为Shim Pack CLC ODS柱(250 mm×4. 6 mm,5μm),流动相为乙腈-0. 05%磷酸溶液(3∶97),紫外检测波长为220 nm,流速为1. 0 mL/min,柱温为25℃。在18. 636～93. 180μg/mL的浓度范围内,天麻素的浓度与其峰面积呈现良好的线性关系(r=0. 99995),平均加样回收率为99. 86%,RSD=0. 74%(n=6)。本方法定量准确、重复性好、稳定可靠,可作为天麻珍珠头痛胶囊中天麻素的含量分析方法。     

盐酸二甲双胍片的含量测定

建立了 HPLC法测定盐酸二甲双胍片的含量。采用 Partisil SCX色谱柱 ,流动相为磷酸二氢铵溶液 (取磷酸二氢铵 1 7g,用水溶解并稀释至 1 0 0 0 m L,用磷酸调 p H至 3 .0 ) ,流速 1 .5 m L/min,检测波长 2 3 3 nm,进样体积 2 0μL,按外标法以峰面积计算盐酸二甲双胍的含量。线性范围为5 4.0～ 2 5 9.2 μg/m L,平均回收率 1 0 1 .6% (RSD0 .6% ,n=9) ,精密度 0 .9% (n=6)     

二安替比林对氯苯基甲烷与钒的显色反应研究

以正交设计法试验研究了二安替比林对氯苯基甲烷试剂分光光度法测定微量钒的最佳显色条件。最佳显色条件为 :(1+5 ) H3PO4 用量为 4 .0 0 m L,0 .2 m ol· L- 1 Mn( )的用量为 2 .0 0 m L,10 g· L- 1 Tween80用量为 2 .0 0 m L ,2 g· L- 1 DAPCM用量为 3.0 0 m L ,加热温度为 90℃ ,加热时间为 5 5 m in,最大吸收波长为 4 85 nm。V( )在 0 .2 0～ 5 .0 0 μg· (2 5 m L) - 1范围内呈良好线性关系 ,线性回归方程为 A=0 .92 11+0 .35 14 C[μg· (2 5m L) - 1 ],线性相关系数 r=0 .9979,摩尔吸光系数 ε=1.0 3× 10 6 [L· (mol· cm) - 1 ]。本法应用于猪骨中钒 ( )的测定 ,结果满意     

正交法在PTA生产中粒径控制上的应用

介绍了正交试验法在PTA生产中粒径控制上的应用。对第一、二结晶器采用L9( 34)正交表进行试验 ,选出最优操作方案为第一结晶器液位为 2 6 %、压力为 3 6 0 0kPa ,第二结晶器液位为 45 .5 % ,压力为 2 40 0kPa ,结果是 :平均粒径从原来的 ( 118± 10 ) μm控制到 ( 118± 8) μm左右 ,粒径小于 45 μm的从原来的 2 0 %下降到 15 %左右 ,粒径 2 5 0 μm以下的由 93 %上升到95 %左右     

三波长分光光度法同时测定食品添加剂

本文采用三波长分光光度法同时测定食品中日落黄和柠檬黄。选择 30 5、347、4 6 4nm为测定日落黄的波长组合 ,其回归方程为ΔΑ =0 0 0 30 93+0 0 135 7C ,r日 =0 9999,线性范围为 3～ 95 μg·mL-1;选择 345、4 4 4、5 0 8nm为测定柠檬黄的波长组合 ,其回归方程为ΔΑ =0 0 0 1392 +0 0 2 5 6 1C ,r柠 =0 9999,线性范围为 4～ 85 μg·mL-1。实验表明 ,本方法很好的消除了日落黄与柠檬黄之间的干扰 ,回收率达到 95 5 6 %～10 2 1% ,RSD日 =0 6 2 31% ,RSD柠 =0 70 89% ,结果令人满意     

新试剂1-(6-硝基-2-苯并噻唑)-3-(4-硝基苯)-三氮烯的合成及分析性能研究

报道了新试剂 1 - ( 6 -硝基 - 2 -苯并噻唑 ) - 3- ( 4-硝基苯 ) -三氮烯 ( NBTNPT)的合成方法。对其分析性能 ,与金属离子镉、汞、锌等显色反应进行了研究。结果表明 :在非离子表面活性剂 Triton X- 1 0 0存在下 ,NBTNPT存在二级离解 ,离解常数分别为 p K1 =6 .1和 p K2 =1 0 .0 ,若应用双峰双波长法测定 ,NBTNPT与 Cd( )、Hg( )、Zn( )显色反应均具有较高的灵敏度 ,其表观摩尔吸光系数分别为 2 .82× 1 0 5、2 .2 1× 1 0 5、1 .76× 1 0 5L·mol- 1 · cm- 1 ,且分别在 0～ 7μg/2 5 m L、0～ 6 μg/2 5 m L、0～ 6 μg/2 5 m L范围内符合比尔定律。     

编与读

1　公顷的符号为 hm2因为 10 0 m× 10 0 m为 1公顷 ,英文 hundred表示百 ,故取其第 1个字母 h,用 hm2表示公顷 ,而不是过去的 ha。2　现在取消亩单位 ,故亩产量常改为 6 6 7m2 产量因为 1公顷 =10 0 m× 10 0 m=10 4 m2 ,1公顷 =15亩 ,故1亩 =10 4 / 15 =6 6 6 .6 · ≈ 6 6 6 .7m2。3　关于 ppmppm表示百万分之一 ,为取消单位 ,现可改用以下 3种表示方法 :(1)　如硫酸尾气含 SO2 10 0 ppm,即百万之 10 0 ,可将其改为 φ(SO2 ) =0 .0 1% ,表示尾气中 SO2 的体积分率为0 .0 1% ;(2 )　又如水中含重金属 Pb5 ppm,即百万分之 5 ,可将其改为…     

高效液相色谱法测定盐酸特芘萘酚乳膏中的盐酸特芘萘酚

确立了丁克制剂中的盐酸特芘萘酚的液相色谱测定方法 ,色谱柱 :C18(15 0× 4 .6mm ,5 μm) ,流动相为甲醇∶乙酸铵 (0 .0 5mol·L-1,乙酸调pH =6 .0 ) =8∶2 ,流速 :1.0 0mL·min-1,检测器为紫外检测器 ,检测波长为 2 83nm ,结果证明此方法测定丁克制剂中的盐酸特芘萘酚是可行的。     

磷酸盐测定新方法的研究

研究发现在聚乙烯醇存在下 ,孔雀绿 钼酸铵能与磷酸发生灵敏的显色反应 ,据此建立一种测定痕量磷的新方法。在 2 5 m L量瓶中 ,加入不多于 1 2 μg磷标准溶液 ,5 m L5 mo L- 1的 H2 SO4 ,5 0 m L孔雀绿 钼酸铵 ,1 0 m L0 .5 %聚乙烯醇 ,用水定容 ,摇匀 ,放入沸水浴中加热 5 min,取出 ,流水冷却。以试剂空白为参比 ,在 635 nm处 ,用 1 cm比色皿于 DU 7HS分光光度计上测定吸光度。试验表明 ,所生成的蓝色缔合物最大吸收波长在 635 nm,表观摩尔吸光系数为9 30× 1 0 4 ,0μg～ 1 2μg P 2 5 m L服从比耳定律 ,回归方程式为 :A=0 .1 2 C+ 0 .0 1 (其中 A为 635 nm处缔合物吸光度 ,C为 2 5 m L溶液中磷的 μg数 )。常温下 ,缔合物可稳定 2 4 h以上。由于反应酸度高 ,有良好的选择性。在测定 5 μg P 2 5 m L时 ,吸光度相对误差在± 5 %以内 ,共存元素允许量如下 (均以 mg为单位 ) :Na+ 、Al3+ 、Ca2 + 、Fe3+ 、Mg2 + ( 1 0 ) ;Pb2 + 、Cu2 + 、Cd2 + 、Co2 + 、Ni2 + 、Mn2 + ( 5 ) ;Cr3+ ( 0 .5 ) ;As( )、Si( ) ( 0 .2 5 ) ;BO3+ 3( 5 ) ;Cl- ( 30 )。该法的测定结果与磷酸杂多酸光度法一致。     

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.     

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。     

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.     

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.