Hf-ZnO酪氨酸酶生物传感器检测邻苯二酚

以四氯化铪(HfCl_4)和六水合硝酸锌为原料,通过水热法制得Hf掺杂氧化锌纳米材料(Hf-ZnO),并将Hf-ZnO、酪氨酸酶(Tyr)和壳聚糖(CS)修饰在玻碳电极(GCE)上,制得Tyr/Hf-ZnO/CS/GCE生物传感器。利用FESEM、DLS、XRD和XPS对Hf-ZnO的结构和性能进行表征。采用循环伏安法(CV)和计时电流法(IT)对Tyr/Hf-ZnO/CS/GCE电极进行电化学测试。结果表明,Tyr/Hf-ZnO/CS/GCE电极在pH=5和–50 mV的低电势下对邻苯二酚有最佳检测能力,对邻苯二酚检测的线性范围是0.5～47.0μmol/L,灵敏度为195 mA/(mol/L),检测限是0.1215μmol/L (S/N=3)。此外,该生物电极的稳定性和重复性较好,可有效避免尿素、多巴胺、抗坏血酸等与邻苯二酚电化学活性相近物质的干扰。     

静电纺丝法制备ZnO构建酪氨酸酶生物传感器检测邻苯二酚

电化学生物传感器在环境监测、生物与食品分析等领域应用广泛。本文采用静电纺丝法制备了氧化锌微纳米纤维材料,并负载酪氨酸酶（Tyr）构建了检测邻苯二酚的生物传感电极。利用X射线粉末衍射（XRD）、扫描电子显微镜（SEM）表征了氧化锌微纳米纤维的形貌结构,采用循环伏安法（CV）和计时电流法（IT）优化了检测邻苯二酚的工作条件。结果表明,制备的Tyr/ZnO/CS/GCE生物传感电极具有良好的电化学性能,在反应过程中为扩散控制,对邻苯二酚的检测在5～50μmol/L的浓度范围内具有较好的线性关系,最低检测限为1.9041μmol/L,灵敏度为376.31μA/(mmol·L·cm²),氧化锌的加入可增强酪氨酸酶的稳定性,在尿素、多巴胺和葡萄糖3种电化学活性相近物质存在的情况下仍对邻苯二酚的检测有较好的选择性,且具有良好的循环稳定性。     

邻对苯二酚在石墨烯-聚噻吩复合膜修饰电极上的电化学行为及测定

研制了一种新型的石墨烯/聚噻吩复合膜修饰玻碳电极(GR/PTh/GCE),在0.100 mol/L的柠檬酸-磷酸氢二钠缓冲溶液中(pH 7.0),利用循环伏安法(CV)研究了该修饰电极对邻苯二酚(CC)和对苯二酚(HQ)的电催化作用,同时利用差分脉冲溶出伏安法(DPSV)测定邻苯二酚和对苯二酚的含量,线性范围为1.00×10-6～4.00×10-4mol/L,检出限为1.50×10-7 mol/L,并应用于模拟废水中邻苯二酚和对苯二酚的测定,回收率分别为98.0％～103.0％、96.0％～104.O％,效果良好.     

微球状Co_3O_4修饰电极检测邻苯二酚

采用水热法在400℃的条件下煅烧并形成Co_3O_4微球,通过XRD粉末衍射、SEM等对Co_3O_4结构及形貌进行表征,并用循环伏安法(Cyclic Voltammetry,CV)和电化学阻抗谱法(Electrochemical Impedance Spectroscopy,EIS)对Co_3O_4的电化学性能进行表征。利用Co_3O_4修饰玻碳电极(Co_3O_4/GCE)并通过方波伏安法(Square wave voltammetry,SWV)检测邻苯二酚,在3.3~33μmol/L的浓度范围内,邻苯二酚浓度和峰电流值呈线性关系,回归方程的相关系数为0.995,检测限(LOD)为0.42μmol/L(3σ法),灵敏度为0.029μA·(μmol/L)-1。同时进行了电极的稳定性实验,经10次循环,其峰电流的相对标准偏差(RSD)为0.25%。还对实际水样进行加标回收实验,该电极对实际水样的检测呈现出良好的性能。     

基于聚亚甲基蓝导电膜的芦丁电化学传感器

将玻碳电极浸入含有亚甲基蓝(MB)的缓冲溶液中,采用循环伏安法沉积得到了聚亚甲基蓝(pMB)导电膜修饰GCE (pMB/GCE)。在以铁氰化钾为分子探针对pMB/GCE的表征中导电性良好。采用微分脉冲伏安法对芦丁进行检测,得到了0.6～20μmol/L范围内检测芦丁的工作曲线,检测限为0.15μmol/L。pMB/GCE在芦丁片的检测中,回收率在102.8%～104.5%范围内。     

基于电沉积金修饰电极的新型无酶葡萄糖传感器研究

通过恒电流电沉积得到了金修饰的玻碳电极(Au/GCE)。采用循环伏安法和计时-电流法考察了此电极对葡萄糖的催化性能。在最佳实验条件下,Au/GCE电极对葡萄糖响应的线性范围为0.001~1.93 mmol/L,检测限可达0.5μmol/L(S/N=3),并且具有较好的抗干扰性。     

自组装纳/微分级结构CoNi前驱体多孔微球对氢醌的选择性检测

开发了一种基于玻碳电极(GCE)表面修饰钴镍前驱体多孔微球(CoNiP/GCE)的电化学传感器,用于选择性测定氢醌。通过SEM、XRD和BET等多种手段对CoNi前驱体进行了表征。运用循环伏安法和示差脉冲伏安法研究氢醌在CoNiP/GCE表面的电化学性能。结果表明:CoNiP/GCE对氢醌有良好的电催化氧化性能。在0.5～5.0 mmol/L检测范围内,DPV峰电流与不同浓度氢醌展现了较好的线性关系,R~2=0.996 8,检测限为3.5μmol/L。此外,修饰电极能够在强干扰物质多巴胺的存在下实现对氢醌的特异性检测,检测范围是0.2～1.8 mmol/L,检测限为2.29μmol/L,R~2=0.992 8。CoNiP/GCE具有良好的选择性和抗干扰能力,适合进一步开发用于生物样品中氢醌检测的传感器。     

一步热解法制备多孔碳-纳米金电极检测酚类

以氯金酸处理过的铁基金属有机框架（Metal Organic Frameworks, MOFs-Fe）材料为模板，通过一步热解法制备了基于MOFs-Fe的热解多孔碳负载金纳米材料（MOFs-Fe Porous Carbon/Au Nanopowders MFPC/Au-NPs）。通过扫描电子显微镜（SEM）及X-射线粉末衍射（XRD）表征了样品的形貌及相纯度，用X射线光电子能谱（XPS）和全自动比表面和孔径分析仪对复合材料所含元素、比表面积及孔径分布进行了测试。通过滴涂法制备了修饰电极（MFPC/Au-NPs/GCE），用循环伏安法（CV）、差分脉冲伏安法（DPV）和交流阻抗法（EIS）测试了邻苯二酚（CA）及对苯二酚（HQ）在此电极上的电化学行为。在pH=7.4条件下，HQ和CA的氧化峰电流在浓度为0.4~20 μmol/L时与浓度呈线性关系，检出限分别为0.039 μmol/L和0.040 μmol/L。该电极检出限低，灵敏度高，为快速检测邻苯二酚和对苯二酚提供了一种简便快速的方法。     

电还原氧化石墨烯修饰电极检测苯二酚异构体

基于氧化石墨烯修饰电极,通过简单的恒电位还原方式制备电还原氧化石墨烯修饰电极(r GO/GCE),采用循环伏安法(CV)和微分脉冲伏安法(DPV)研究了对苯二酚(HQ)、邻苯二酚(CT)、间苯二酚(RS)3种苯二酚异构体混合物在该电极上的电化学响应,并将检测条件逐步优化。结果表明,r GO/GCE可用于同时检测苯二酚的3种同分异构体,HQ、CT在r GO/GCE上的电位差为141.29 m V,CT、RS间的电位差为323.81 m V,线性范围分别为5.00×10~(-5)~2.00×10~(-3)、5.00×10~(-5)~2.00×10~(-3)、7.00×10~(-5)~3.00×10~(-3)mol/L,检出限分别达到3.57×10~(-7)、3.62×10~(-7)、3.55×10~(-6)mol/L。并将所制备电极应用于模拟水样,获得满意结果。     

基于葡萄糖酸锌衍生碳源制备同时检测邻/对苯二酚的电化学传感器

为实现邻苯二酚(HQ)和对苯二酚(CA)的快速、灵敏检测,以NaC1作为模板、葡萄糖酸锌(sodium gluconate)为碳源,通过溶解-重结晶制备碳前驱体,同时热解制备多孔碳材料(ZGDPC)并将其用于构建电化学传感器ZGDPC/GCE.使用扫描电子显微镜(SEM)、X射线粉末衍射(XRD)及比表面积分析仪分别对其形貌和结构进行了表征,然后通过差分脉冲伏安法(DPV)考察了ZGDPC/GCE表面HQ和CA的电化学行为.优化条件下,HQ的线性检出范围为0～25 μmol/L,检出限为0.124 μmol/L,CA的线性检出范围为0～30 μmol/L,检出限为0.213 μmol/L.该传感器对实际水样中HQ和CA的回收率为95.6％～102.3％.以上结果表明,基于该电化学传感器能实现实际样品中对HQ和CA的同时检测.     

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.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008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、不饱和聚酯树脂、环氧树脂)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.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006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生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。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（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。