离子色谱法测定真空塑料采血管中氟化物添加剂的含量

建立离子色谱法测定真空塑料采血管中添加剂氟化物含量的方法 ,并探讨该方法测定不同型号规格样品的效果。将样品用超纯水分次洗出并定容至适宜容量瓶中,以3.2 mmol/LNa_2CO_3和1.0mmol/L NaHCO_3溶液为淋洗液,采用Metrosep A supp5色谱柱(150×4.0 mm,5μm),抑制器电流取65.0mA,流速为0.7 mL/min,直接进样,进样体积20μL,色谱柱柱温30℃,进行电导检测并通过峰面积定量。利用该方法对样品中氟化物进行测定,线性相关系数为0.9999,平均回收率为99.26%～100.69%,相对标准偏差为0.32%～0.68%,氟离子的最小检测浓度为0.004 mg/L。该方法简便、快捷、准确度高、特异性好,能满足塑料采血管中单一抗凝剂氟化钠、联合抗凝剂氟化钠/EDTA二钾、氟化钠-草酸钾中氟化物的含量测定。     

质量控制图在离子色谱法测定水中硫酸根离子的应用

采用ICS900离子色谱仪,对同一硫酸根离子质控样品进行浓度测定,收集20组有效数据,并统计分析,绘制出离子色谱法测定水中硫酸根离子含量的均值-极差质量控制图。结果表明,离子色谱法测定水中硫酸根离子浓度的受控范围为37.99～38.76 mg/L,警戒限为0.31 mg/L,辅助限为0.15 mg/L。通过建立实验室硫酸根离子质控样品均值-极差质量控制图能够实现对分析方法、测试系统稳定性以及重复性的实时监控,及时发现异常并做出相应的纠正和预防措施,确保检测结果准确可靠。     

高温水解-离子色谱法测定铁矿石中氟和氯

采用高温水解铁矿石-氢氧化钠溶液吸收装置,建立了高温水解前处理铁矿石样品,离子色谱法同时测定铁矿石中氟和氯的分析方法。样品与水解催化剂V2O5的质量比为1∶1,采用两组氢氧化钠溶液作为吸收剂。系统、全面地考察了测定方法的影响因素,并确定了水解温度1100℃,水解时间30 min,氧气流量400～500 m L/min为最优高温水解预处理铁矿石;优化离子色谱法条件;方法的线性相关性比较好(r0. 999)。     

离子选择电极法测定磷石膏中全氟含量

磷石膏中的氟限制了磷石膏在水泥和建材等领域的应用,因此了解磷石膏中的氟含量非常重要.对磷石膏中的氟含量的测定方法进行了探讨.通过实验提出了用碳酸钠熔融磷石膏样品,用柠檬酸钠-冰醋酸作为总离子强度调节缓冲溶液,采用离子选择电极法测定磷石膏中的全氟含量.该方法氟离子质量浓度检出限为0.34 mg/L,氟离子回收率为88.5%～90.3%,氟离子质量浓度线性范围为0～5 mg/L,线性相关系数R2=0.999 1,相对标准偏差为1.2%(n=7).该方法是一种简便、快捷、灵敏度较高的测定磷石膏中全氟含量的方法.     

高效离子色谱仪测定工业锅炉水中阴离子含量

采用化学抑制-电导-离子色谱法测定工业锅炉水中阴离子,分离柱温度控制在30C,以4.5 mmol/L Na2CO3、0.8 mmol/L NaHCO3为淋洗液,流速1.2 mL/min,6种阴离子在22.20 min完成检测.各离子的检出限0.002 ～ 0.01 mg/L,本法精密度小于2％,线性范围较宽,水样中各阴离子的平均加标回收率98.5％～101.6％.该法适合工业锅炉水中阴离子含量测定.     

离子色谱法测定硅氟酸中的硫酸根

采用离子色谱法对硅氟酸中的硫酸根进行测定。样品用盐酸挥发排除硅氟酸中的氟离子,采用883Basic IC Plus型离子色谱仪测定。方法的线性范围:0~20μg/m L,检出限:0.098μg/m L,,相关系数0.999,加标回收率在98%~103%之间。结果表明,此方法操作简单,分析速度快,准确,能满足生产需要。     

离子色谱法与滴定法测定水溶肥料中亚磷酸盐含量的试验研究

采用离子色谱法和常规滴定法测定水溶肥料中亚磷酸盐(以HPO₃^2-计)的含量,考察了两种方法的精密度、加标回收率和离子色谱法的检出限。结果表明:滴定法测定结果的相对标准偏差(RSD)为1.04%～1.26%,加标回收率为90.20%～96.10%;离子色谱法测定时,亚磷酸的质量浓度在1.0～50.0μg/m L与峰面积呈线性关系,方法的检出限为40 mg/kg,RSD为0.78%～1.07%,加标回收率为95.20%～98.60%。两种方法均可满足水溶肥料中亚磷酸盐含量的测定要求,离子色谱法的测定结果更准确,操作更快捷。     

离子色谱法测定水泥中氯离子含量要点探究

根据水泥样品的特点，建立了离子色谱法测定水泥中氯离子含量的方法。试验采用Metrosep A Supp 5-250/4.0阴离子交换色谱柱，以碳酸氢钠和碳酸钠为淋洗液，流速为0.700 m L/min，抑制型电导检测器。试验结果表明氯离子可以较快地分离，并且与常见成盐阴离子分离良好。通过大量的验证试验，文章对离子色谱法在水泥中氯离子测定的技术应用做出了明确的概述与分析。离子色谱法有着快速、灵敏而又精准的特点，在水泥分析领域之中，有着极为广阔的发展前景。     

生活饮用水中氟离子含量的测定

为获取昭通市昭阳区生活饮用水中氟离子含量的科学数据和检测氟离子含量是否在国家规定标准要求内,通过氟离子选择电极法对昭通市昭阳区八个地方的生活饮用水中氟离子含量进行了测定,测得各水样的p H值在6. 66～7. 63之间,氟离子含量在0. 0551～0. 1512 mg/L之间,且氟含量都符合国家标准值(0. 05～1. 0 mg/L)。所测定的氟离子加标回收率范围在93%～97%,RSD在0. 15%～1. 18%之间,说明本实验所采取的方法便捷有效,氟离子选择电极法测定准确,可靠。     

离子色谱法测定喹啉铜原药中硫酸钠含量

建立了一种离子色谱法测定喹啉铜原药中硫酸钠含量的方法。采用Schodex IC SI-50型分离柱,用3.2 mmol/L碳酸钠和1.0。mmol/L碳酸氢钠混合溶液作流动相,流速为0.8mL/min。外标法进行定量分析,在2.0～10.0 mg/L范围内线性相关系数为r2=0.9999,测得回收率在96.3%～101.6%之间,样品测定的标准偏差为6.76×10^-3,变异系数为1.01%。     

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。