非水溶剂电位滴定法测定标准物质RDX和HMX的含量

建立了在非水溶剂中电位滴定测定纯度标准物质RDX和HMX含量的方法,通过实验对非水溶剂、滴定剂种类、滴定剂浓度、滴定终点进行了选择.通过实验确定了溶剂为二甲基亚砜(DMSO),滴定剂为甲醇钠(CH3ONa),滴定剂浓度为0.30mol/L,终点为电位曲线的等当点,实验用电位滴定曲线准确确定了滴定终点.通过18次测定,测得RDX的纯度为99.554%～99.865%,精密度为0.0976%.测得HMX的纯度为99.565%～99.888%,精密度为0.10%.该法简便、可靠.     

自动电位滴定法测定碳酸氢钠中氯化物含量

目的:建立碳酸氢钠中氯化物含量的自动电位滴定测定方法。方法 :样品用去离子水溶解后,用硝酸银标准溶液为滴定液,用自动电位滴定仪测定氯化物含量。结果:电位滴定法测定碳酸氢钠中氯化物含量的检出限为0. 8mg/L,定量限为3. 2mg/L;加标回收率在96.8%～105. 4%之间;重复性精密度RSD为0. 024%(n=7);样品溶液酸碱度对测定结果无影响。结论:本方法安全环保、准确、便捷,可用于碳酸氢钠中氯化物含量的测定。     

自动电位滴定仪测定循环液中碱度

目的:本着提高工作效率,建立了一种操作简单、准确测定循环液中碱度(KHCO3)的自动电位滴定法。方法:5 m L样品中加入50 m L无二氧化碳水,使用0.5059 mol/L盐酸标准溶液进行自动电位滴定,当p H=4.2到达滴定终点,根据消耗盐酸标准溶液体积测定循环液中KHCO3的含量。结论:与用于循环液中KHCO3含量测定的手动滴定比较,自动电位滴定法具有样品用量少、仪器操作简单、终点判断准确,灵敏度高、测量数据准确,适合硫磺回收循环液中KHCO3含量的检测。     

对苯二甲酸残渣中总酸含量的测定

通过实验改进并总结了氧化残渣系统浆料总酸含量的测定方法,提出在滴定前加入吡啶作溶剂,EDTA作掩蔽剂,有效改善了滴定速度慢、终点判定不准的情况,成功实现了残渣系统浆料总酸含量的准确测定。     

原油中碱性氮含量电位滴定法测定研究

目的:准确分析原油中碱性氮含量分布,可为原油加工提供更合理的方案.方法:建立了原油中碱性氮含量的测定方法,讨论了方法检出限以及进行加标回收试验,对滴定过程及混合溶剂进行优化.结果:采用电位滴定法测定原油的碱性氮含量重复性和准确性比较理想.结论:克服了原油颜色深,没有合适的指示剂确定滴定终点的难题.     

酚醛增粘树脂酸值测定方法的研究

对比常见的13种酸值测定方法,研究溶解溶剂、滴定液溶剂、指示剂、常规化学指示剂滴定和电位滴定对酚醛增粘树脂酸值测定结果的影响。结果表明：因树脂酸值测试不同于常规的酸碱中和反应,无明显反应终点,无论是指示剂滴定或电位滴定,本质上都是设置了某个pH值作为滴定终点,因测定方法不同,滴定终点的pH值不同,树脂酸值测定结果并不可比,但不同方法下树脂酸值的变化趋势具有一致性。     

微库仑法测定重整原料中微量硫含量影响因素的研究

对重整进料中微量硫含量的微库仑测定方法进行了研究,验证了偏压、气体流量、裂解温度、滴定池、电解液、进样速度等多个影响因素。根据实际测定样品,对行业标准中操作条件进行了优化,确保了重整原料中硫含量测定分析的准确性。     

温度滴定法测定导热油中总酸值

以导热油为样品,利用瑞士万通859温度滴定仪,建立了油品中总酸含量的测定方法,且与自动电位滴定方法进行了对比。测试结果表明,温度滴定法测得样品中总酸含量在0.13 mg KOH·g~(-1)~2.2 mg KOH·g~(-1)之间,样品相对标准偏差值(RSD)均在1.5%以下。利用温度滴定原理测定油品中总酸方法准确可靠,终点突跃明显,重复性良好,适用于导热油等复杂基质样品中总酸测定,且可实现全自动测样分析。     

巴洛合成母液中3-甲胺基哌啶盐酸盐含量测定

建立巴洛合成母液中3-甲胺基哌啶盐酸盐的分离、分析测定方法。根据样品中各组分溶解性差异,采用了柱层析分离的方法。中性A1203层析柱,用丙酮淋洗出试样中的有机杂质,再用甲醇钠-甲醇溶液淋洗,分离出母液巾3．甲胺基哌啶盐酸盐。用气相色谱法进行测定：采用毛细管柱,固定液为OV-101,90-240℃程序升温,苯甲酸甲酯为内标物,测定3-甲胺基哌啶盐酸盐的含量,平均含量2．43％,准确度98％,精密度0．02。所建立的方法简单、快速、重复性好,结果准确,精密度好。     

硝酸银电位滴定法测定盐酸羟考酮注射液中氯化钠含量

采用硝酸银电位滴定法测定盐酸羟考酮注射液中总氯量,根据注射液的含量,计算样品溶液中盐酸羟考酮的含氯量作为本底扣除,得注射液中氯化钠的量,本品氯化钠含量在4.50～54.03 mg范围内与硝酸银滴定液消耗体积呈良好的线性关系(r=1.0000,n=6),所得线性回归方程为V=0.1634C+0.0103。方法学考察准确性、重现性及回收率试验均符合要求。本方法滴定终点灵敏,能用于准确地测定盐酸羟考酮注射液中氯化钠含量。     

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。     

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.