黄瓜中百菌清残留量的气相色谱分析

本实验主要研究用气相色谱法分析在1立方米空间放含百菌清有效成分0.1克东农1号烟剂时,百菌清在黄瓜中的残留。使用GC—9A气相色谱仪的电子捕获检测器,灵敏度为2.9×10~(-20)毫伏·毫升/毫克,最小检测量4.6×10~(-11)克,实验精确度较高。     

气相色谱法测定四氧化二氮中相当水含量

叙述了气相色谱法测定四氧化二氮产品中相当水含量。该分析方法是参照美国军用规范MIL-P-26539C-76研究的。试验验证,该法可适用于四氧化二氮产品中相当水含量的常规分析,方法的标准偏差2.00×10~(13)％～7.46×10~(-3)％,回收率98.45％～108.37％。     

空气中甲拌磷的采集和测定方法研究

本文介绍用一种新型固体吸附剂——聚氨酯泡沫塑料采集空气中甲拌磷,然后用气相色谱法进行分析。操作简单、携带方便、分离效果好,采样效率达95%以上。最小检测量为5×10~(-11)克。并对样品的处理方法进行了研究,提出用“直接浸泡法”代替“索氏提取法”,省时、省力,提取效率达96%以上。本法对甲拌磷的最低检测量为5×10~(-11)克。     

全二维气相色谱-飞行时间质谱法分析香水中的化学成分

采用一维气相色谱-飞行时间质谱法(1DGC TOF-MS)和全二维气相色谱-飞行时间质谱法(GC×GC TOFMS)分析了香水的组成情况,对部分常见物质进行了定性分析。结果表明,对于同一香水样品,1DGC TOF-MS只鉴定出样品中匹配度大于750的共172种化合物,分别为萜烯类34种、醇类25种、酯类37种、醚类15种、酮类23种、醛类12种、酸和其他杂环烃类26种;GC×GC TOF-MS软件对经过数据自动处理,并结合标准谱图辅助定性和手动扣除,定性出匹配度大于750的共722种化合物,分别为萜烯类125种、醇类168种、酯类79种、醛类33种、酮类92种、其他杂环和饱和长链烃类等225种。     

高效液相色谱法在二元酸分析中的应用

用高效液相色谱法分析丁二酸、戊二酸和己二酸的混合物,分析采用Waters-ODS色谱柱、4×150 mm色谱柱、紫外检测器,用含甲醇20%(V/V)的磷酸-磷酸二氢钾缓冲溶液为流动相。该方法与气相色谱法相比,具有样品不需预处理、操作简单、分析速度快等优点。     

蔬菜中十六种农药残留的SIM-GC-MS分析

采用选择离子–气相色谱–质谱联用(SIM–GC–MS)方式,依据保留时间和特征离子丰度比,可以在30min之内检测有机磷(甲基对硫磷、甲拌磷、甲基异柳磷、马拉硫磷、毒死蜱、倍硫磷)、有机氯(敌敌畏、七氯、百菌清、α-六六六、γ-六六六、δ-六六六、p,p'-DDE、p,p'-DDD)、除虫菊酯(甲氰菊酯)、三唑酮等16种农药。通过优化色谱条件,可对16种农药同时进行定性和定量分析。建立了各种农药的标准曲线并计算回收率和最低检测限;标准曲线的线性关系良好,相关系数为0.997;平均回收率在75%～105%之间;检出限一般在8.8×10-4～2.6×10-3μg/g,基本上满足了多残留农药分析的要求。     

高温高压下尿素溶液中溶解氧的测定

采用特殊的取样装置,以气相色谱法测定尿素-甲铵液(以下简称尿液)中微量溶解氧.具有简便、快速、准确度高、测定重现性好等优点.其最小检测浓度小于1×10-6.适用于对高温、高压下尿液中溶解氧的快速测定.     

氰戊菊酯及其中间体的气相色谱分析

氰戊菊酯是广谱性拟除虫菊酯类杀虫剂,化学名称(RS)-α-氰基-3-苯氧基芳基(RS)-2-(4-氯苯基)异戊酸酯。其原药、乳油和残留分析有气相色谱、高压液相色谱、毛细管色谱法。在此我们介绍氰戊菊酯及中间体α-(?)丙基-对-氯苯乙酰氯的气相色谱分析。一、氰戊菊酯我们选用8%SE-30/Chromosorb W AW DMCS (80～100目)3.5毫米×0.5米玻璃     

不同碳源对4种亚硝化反硝化聚磷菌脱氮除磷的影响

为了更加深入地了解亚硝化反硝化聚磷菌(NDPAOs)对碳源的需求,对NDPAOs的葡萄球菌属(Sta.)、副球菌属(Par.)、克雷伯氏菌属(Kle.)和芽孢杆菌属(Bac.)通过纯培养的方式研究了不同碳源对其脱氮除磷的影响。结果表明,4种NDPAOs最容易利用的碳源均是葡萄糖。厌氧条件下,4种NDPAOs对COD的单位细胞降解量均是以葡萄糖为碳源时最高,降解量分别为3.9×10-6、3.5×10-6、2.2×10-6和2.6×10-6mg/cfu;其分别以丙酸钠、乙酸钠和蔗糖、乙酸钠以及丙酸钠为碳源时释放的磷酸盐最多,释放量分别为6.9×10-9、4.0×10-9、2.8×10-8和6.2×10-9mg/cfu。缺氧条件下,4种NDPAOs分别以丙酸钠、葡萄糖、葡萄糖和丙酸钠为碳源时消耗的亚硝酸盐最多,同时吸收的磷酸盐量最高,消耗的亚硝酸盐量分别为8.1×10-8、8.1×10-8、4.1×10-8和6.4×10-8mg/cfu,吸收的磷酸盐量分别为1.5×10-8、1.3×10-8、9.6×10-9和1.3×10-8mg/cfu。     

喹啉极谱特性的研究

本文介绍了用单扫描示波极谱法测定喹啉的实验条件、机理和某些无机离子、有机物的干扰、回收实验,结果满意,方法简单、快速、准确、容易推广。对喹啉的测定方法,常用气相色谱法,液相色谱法、薄层色谱法和分光光度法。用极谱法研究喹啉的报道不多,文献提出在强酸介质中测定喹啉的方法其检测范围为10~(-3)M～10~(-5)M,机理为氢催化波,而本方法测定喹啉的最低检出限为4×10~(-6)M,机理为吸附催化波。     

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.     

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。     

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。