核磁共振波谱内标法测定四氯虫酰胺标样的含量

[目的]采用核磁共振波谱内标法,建立了快速、专属、准确测定四氯虫酰胺标样含量的方法。[方法]使用日本电子公司JNM-ECZ600R超导核磁共振波谱仪,以氘代二甲基亚砜为溶剂,顺丁烯二酸为内标,在测定温度25℃、脉冲宽度8.0μs、延迟时间为5 s、扫描次数8的条件下采集样品氢谱。[结果]以化学位移δ分别为10.55和6.27的四氯虫酰胺和顺丁烯二酸的氢质子峰作为定量峰,其峰面积比y(As/Ar)与质量比x(ms/mr)进行线性回归,相关系数为0.9999。含量测定重复性试验的RSD值为0.38%,稳定性的RSD值为0.77%,测得四氯虫酰胺标样的含量为99.6%。[结论]在没有标准对照品的情况下,核磁共振波谱法可用于四氯虫酰胺的含量测定,该方法具有快速、准确、简便的优点。     

PTMG-b-PET共聚酯的合成及性能

以对苯二甲酸、乙二醇以及聚四氢呋喃(PTMG)为原料,采用熔融缩聚法合成了不同PTMG比例的聚对苯二甲酸乙二醇酯-聚四氢呋喃(PET-PTMG)聚醚酯,研究了PTMG含量对共聚酯缩聚反应过程的影响。利用红外光谱法、核磁共振波谱法分析了共聚酯结构、序列分布,利用差示扫描量热分析(DSC)、热失重分析研究了共聚酯热性能、结晶动力学以及热稳定性。研究表明,投入体系的聚醚基本都进入了聚合物分子链;PTMG含量增加,聚合反应动力黏度增长变缓,共聚酯玻璃化转变温度(T_g)、结晶温度(T_c)、熔点(T_m)均明显降低,熔融结晶温度(T_mc)先上升后下降,试验制备的共聚酯较常规PET结晶速率更快。在氮气氛围中,共聚酯的热降解为一阶反应,PTMG含量增加,共聚酯热稳定性明显降低。     

核磁共振波谱法测定废水中二氯甲烷的含量

建立了核磁共振波谱(NMR)法测定废水中二氯甲烷含量的方法。以重水为溶剂,以基准物质邻苯二甲酸氢钾为内标(邻苯二甲酸氢钾和二氯甲烷的定量峰化学位移分别为δ=7.45和δ=5.35)。设定脉冲宽度为3.0 s、延迟时间为1.0 s,采样次数为1024次。实验结果表明,测定结果的相对标准偏差(RSD)为0.81%,二氯甲烷质量浓度在500～5 000 mg/L范围内的线性相关系数为0.998。测试的2个实际废水样品中,二氯甲烷的质量浓度分别为1046.8 mg/L(RSD=0.97%)和3492.5 mg/L(RSD=0.83%)。采用该方法测定的结果与顶空气相色谱法结果较吻合,表明核磁共振波谱法可用于废水中二氯甲烷含量的检测。     

磺胺甲基嘧啶纯度定值研究

采用氢定量核磁共振法和质量平衡法对磺胺甲基嘧啶纯度进行定值。通过Bruker-AvanceⅢ400型核磁共振波谱仪,noesyigld 1d脉冲序列,以尼泊金乙酯为内标、氘代DMSO为溶剂,在恒温298 K、谱宽为15×10^-4%、中心激发偏置为5.41×10^-4%、弛豫时间为7 s、扫描次数为32、空扫16次的条件下,采集¹H-qNMR光谱数据。以磺胺甲基嘧啶化学位移(δ6.56)为定量峰,尼泊金乙酯化学位移(δ4.25)为内标峰,¹H-qNMR测得磺胺甲基嘧啶纯度为96.55%,测定精密度RSD为0.089%,重复性RSD为0.24%。质量比Y(m_s/m_r)在2.014~4.051范围内与峰面积比X(A_s/A_r)呈线性关系,线性回归方程为y=0.6071x+0.0049(R2=0.9999)。结果表明,¹H-qNMR与质量平衡法测定结果具有一致性。因此,氢定量核磁共振法可用于磺胺甲基嘧啶含量测定,该方法具有准确、简便的优势。     

SIS热塑性弹性体的波谱分析

通过紫外、红外、质子核磁共振等波谱手段对SIS进行了结构分析,并建立了测定SIS中结合苯乙烯含量的波谱分析方法。     

核磁共振波谱基本原理教学设计

针对有机波谱分析的特点和难点,对核磁共振波谱部分基础理论知识进行教学设计,使学生理解核磁共振波谱的基本概念、常用术语和基本原理,掌握核磁共振与有机化合物分子结构之间的关系,并且掌握运用核磁共振谱解析分子结构的方法,培养科学素养,为学生后续的学习、毕业论文的撰写和深造或从事相关工作奠定基础。     

Al2O3/SiO2对铝硼硅酸盐玻璃结构与性能的影响

采用高温熔融法制备了铝硼硅酸盐玻璃。通过改变玻璃组成中Al₂O₃/SiO₂比,研究了玻璃组成对玻璃性能的影响。通过光电子能谱(XPS)和核磁共振波谱(NMR)分析了玻璃的结构。结果显示,在Al离子多的玻璃中,Al离子主要形成[AlO₄]结构和少量五配位[AlO₅]、六配位铝[AlO₆]结构,Si离子主要形成Q4结构;在Si离子多的玻璃中,Al离子主要形成[AlO₄]结构,Si离子主要形成Q⁴和Q³结构。随着Al₂O₃/SiO₂比的增大,玻璃中桥氧(BO)数减少,形成[BO₄]和[BO₃]构成的硼氧环结构。这些玻璃结构的变化导致玻璃的热膨胀系数、玻璃转变温度和玻璃软化温度随着Al₂O₃/SiO₂比的改变而变化。     

骨架结构醚基支链型羧酸在铝电解电容器中的应用

液态铝电解电容器电解质的发展目前主要集中在支链多元羧酸及其盐,但相应电解液的高温稳定性及低温性能均有待提高。为了解决这一问题,本文通过将骨架结构和醚基相结合,制备了3种骨架结构醚基支链型羧酸(EBCS₁、EBCS₂、EBCS₃),并采用核磁共振波谱和红外光谱对其进行了表征确认。然后通过电解液合成体系的优化,确定了在140℃的烧煮温度下,溶剂体系选用70%乙二醇和10%γ-丁内酯,3种EBCS电解质的最佳含量分别为3.5%、3.5%、3%时电解液具有最优的电性能,电导率均能达到1.8mS/cm,闪火电压均高于550V。将3种电解液装配成铝电解电容器,其室温下的容量、损耗、等效串联电阻ESR和漏电流均优于市售电容器,同时在低温阻抗测试和高温寿命实验中性能表现优异,具有较大的市场应用潜力。     

SIS热塑性弹性体的波谱分析

通过紫外、红外、质子核磁共振等波谱手段对ＳＩＳ进行了结构分析，并建立了测定ＳＩＳ中结合苯乙烯含量的波谱分析方法。     

富勒烯对甲基苯胺衍生物的合成及其对硝化棉安定性的影响

以富勒烯(C₆₀)、溴素(Br₂)、八溴富勒烯(C₆₀Br₈)及对甲基苯胺(C₇H₉N)为原料,经两步反应合成了富勒烯对甲基苯胺衍生物C₆₀(NC₆H₄CH₃)_n;采用核磁共振碳谱(¹³C-NMR)、质谱(MS)、X射线光电子能谱(XPS)、傅里叶变换红外光谱仪(FT-IR)以及紫外-可见光分光光度计(UV-Vis)对合成得到的富勒烯对甲基苯胺衍生物结构进行了表征;采用差热分析(DTA)、真空安定性测试(VST)、热重分析(TGA)、甲基紫实验等热分析方法,并结合电子顺磁共振波谱法研究了富勒烯对甲基苯胺衍生物与硝化棉的相互作用规律和机理。结果表明,富勒烯对甲基苯胺衍生物将甲基紫试纸的变色时间由56min延长至95min;将单位质量硝化棉热分解释放的气体量由2.67mL/g降至1.46mL/g;将硝化棉的热失重率由17.17%降至5.46%;当富勒烯对甲基苯胺衍生物的质量浓度为0.76g/L时,其对氮氧自由基的清除率达到50%。表明富勒烯对甲基苯胺衍生物提高了硝化棉的安定性,且安定性能明显优于传统安定剂DPA和C2。     

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。     

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。     

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.