胶束增敏双硫腙分光光度法测定痕量铅

用异丙醇作溶剂溶解双硫腙,Tween-20作为增溶剂,在盐酸介质中,双硫腙水相直接光度法测定水中痕量铅。铅与双硫腙配合物的最大吸收波长为480nm,铅离子在0～150μg/L浓度范围内呈线性,相关系数r=0.9962,回收率为99.4%～101.4%。     

催化动力学分光光度法测定微量的汞

在pH=4.0的乙酸-乙酸钠缓冲溶液中,微量的Hg(Ⅱ)对亚铁氰化钾与1,10邻-菲啰啉(1,10-0-phen)显色反应有催化作用,加入硫脲能提高其灵敏度,显色程度与Hg(Ⅱ)量在一定范围内呈线性相关,借此建立测定微量Hg(Ⅱ)的分光光度法。实验表明,有色溶液最大吸收波长为515 nm,摩尔吸光系数ε=3.72×106L/(mo.lcm),相关系数为r=0.999 1,催化程度与Hg(Ⅱ)浓度在(0.0~1.2)μg/25 mL范围内符合比耳定律,选择性好,利用该方法直接测定人工合成水样中汞的含量,以及河水、池塘水中微量汞的含量分析,结果满意。     

胶束增溶分光光度法测定水溶液中的汞

研究了Hg(Ⅱ)-双硫腙(H2Dz)-十二烷基磺酸钠三元络合物显色体系,该体系的最大优点是可在水相中直接用光度法测定水样品中的汞含量.络合物的最大吸收波长490 nm,ε490=7.0×104L(mol·cm)-1,汞浓度在0.5～2.3 μg·mL-1范围内符合比尔定律.对样品进行回收实验,得到了很好的效果.     

高灵敏度显色反应测定水中痕量汞的研究

探讨水中汞的分光光度测定方法.在β-环糊精和曲拉通X-100存在下,基于汞与2-(5-溴吡啶-2-偶氮)-5-二乙氨基苯酚的显色反应,采用分光光度法进行测定.结果表明,配合物的最大吸收波长为565 nm,表观摩尔吸光系数为4.60×105L/(mol·cm),汞质量浓度在0～960μg/L范围内服从比尔定律,线性回归方程:A=0.002 3 c 0.007 1(c为汞的质量浓度,μg/L),相关系数r=0.998 4.本方法已用于水中痕量汞的测定,结果令人满意.     

高锰酸氧化苯酚红褪色光度法测定微量锰

在硫酸介质中 ,高锰酸氧化苯酚红褪色 ,由此建立了光度法测定微量锰的方法。锰含量在 0— 4 0μg/ 2 5m L范围内符合比耳定律。其表观摩尔吸光系数为ε=2 .0 4×10 4 。用于天然水中微量锰的测定 ,结果令人满意。     

新显色剂的合成及在环境样品中汞离子的检测研究

研究了十六烷基三甲基溴代铵(CTMAB)存在下汞离子与显色剂形成配合物从而进行分光光度法检测汞的最佳测试条件。汞离子与显色剂在波长405nm处有最大吸收,Hg2+的含量在1.5～100μg/25mL范围内符合朗伯比尔定律,表观摩尔吸光系数ε=0.191×105L·mol-1·cm-1,直线回归方程为:A=0.0039C-0.0029,相关系数为r=0.9984,摩尔比法测定配合物的组成比为n(Hg2+):n(显色剂)=1:2。     

罗丹明B光谱探针测定祛斑霜中微量汞

罗丹明B为光谱探针,研究了在三羟甲基氨基甲烷-HCl缓冲溶液(pH=6.5)中,十二烷基苯磺酸钠(SDBS)存在下,分光光度法测定祛斑霜中微量汞离子,得出了测定的优化条件.实验表明,室温下罗丹明B-SDBS-Hg2+形成水溶性三元复合物,最大吸收波长为554 nm,表观摩尔吸光系数ε=2.43×105L·mol-1·cm-1.Hg2+质量浓度在0～3.00μg/mL范围内服从朗伯-比尔定律.检出限为0.021μg/mL,加标回收率为98.5%～100.3%,RSD为1.06%～1.11%.     

二苯碳酰二肼分光光度法测定水样中的汞

以硼砂-氢氧化钠作为缓冲溶液,在溴化十六烷基三甲胺(CTMAB)及OP乳化剂存在下,Hg2+与过量二苯碳酰二肼(DPC)反应生成稳定的络合物,据此建立了二苯碳酰二肼光度法测定微量汞的方法。最大吸收波长为550 nm,表观摩尔吸光系数(ε550)为9.70×104L·mol-1·cm-1,Hg2+含量为0~1.4μg/mL范围内符合比尔定律,检出限为14.1μg·L-1。方法相对标准偏差(RSD,n=5)为1.1%~2.0%,回收率为98.6%~101.6%。采用本法,测定了污水及实验室废水中的微量汞,结果满意。     

氯化银比浊法测定炉水中的微量氯离子

用硝酸调节炉水的酸度,氯离子与硝酸银反应生成氯化银沉淀,用氯化银分光光度法,测定炉水中的微量氯离子。测定波长为410nm,线性范围15～2200μg/L。结果表明：其吸光值的大小与氯离子生成沉淀的多少成正比,符合朗伯一比尔定律。该法准确、快速、简便、安全,其它的常见离子无干扰。     

薄层树脂相吸光光度法同时测定痕量Fe(Ⅲ)和Fe(Ⅱ)的研究

Fe(Ⅲ)和Fe(Ⅱ)能在弱酸性条件下与邻菲啉(phen)生成稳定有色配合物[Fe(phen)]3 和[Fe(phen)]2 。该配合物能与阳离子交换树脂定量交换缔合,形成树脂(R-)-Fe(Ⅲ)-phen或(R-)-Fe(Ⅱ)-phen三元配位缔合体系。Fe(Ⅱ)表观摩尔吸光系数εF51e(2Ⅱ)=1.03×105L.mol-1.cm-1,比水相光度法提高21倍;测定Fe(Ⅱ)线性范围0~8.0μg/mL。400nm处Fe(Ⅲ)表观摩尔吸光系数4Fε0e(0Ⅲ)=2.6×104L.mol-1.cm-1,比水相光度法提高12倍;Fe(Ⅲ)测定线性范围0~12μg/mL。512nm处测定4.0μg Fe(Ⅱ)6次,RSD=1.37%;400nm处测定4.0μg Fe(Ⅲ)6次,RSD=2.74%。实测了天然水中Fe(Ⅲ)和Fe(Ⅱ)含量,并与AAS法测定结果比较,结果令人满意。     

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.     

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.     

基于ATRP法制备的触角状亲水性羟胺树脂的吸硼性能的研究

以大分子引发剂氯乙酰化聚苯乙烯微球(PS-acyl-Cl)经原子转移自由基聚合(ATRP)法引发丙烯酰胺(AM)和甲基丙烯酸缩水甘油酯(GMA)单体的共聚接枝,制得一种触角状亲水性环氧载体(PS-acyl-g-P(AM-co-GMA)),再经二乙醇胺(DEA)的环氧基开环胺化反应,得到一种含多个-NCH2CH2OH螯合配基的多齿-五元螯合环的触角状亲水性羟胺树脂(PS-acyl-g-P(AM-co-GMA)-DEA)。将此树脂用于硼吸附研究,结果表明,PS-acyl-g-P(AM-co-GMA)-DEA树脂对硼的吸附满足Langmuir方程,为单分子层吸附;饱和吸附量约为37.7 mg·g-1,且树脂5 min即可达到吸附平衡,与其它已报道的吸硼树脂相比,该树脂具有更高的吸附量和吸硼速率。吸附动力学研究表明,树脂吸附硼的过程主要由颗粒扩散过程控制。重复使用5次后该树脂的吸附量基本不变,解吸率均在90%以上,重复使用性能良好。