碘离子选择性电极测定海带、紫菜中碘及碘的浸出率

提出了用碘离子选择性电极测定海带、紫菜中碘的方法。在 0 .2 0 mol/L KNO3 ,1 .0× 1 0 -3mol/L Na2 SO3 ,p H 5 .0～ 6.0溶液中 ,碘离子浓度对数值在 5 .0× 1 0 -7～ 1 .0× 1 0 -1mol/L范围内与电位呈良好线性关系 ,检出限为 3× 1 0 -7mol/L,准确测定了海带、紫菜中碘的含量 ,对浸泡时间与海带中碘的浸出率关系进行了研究。回收率 95 %～ 98% ,相对标准偏差小于 2 .6%。     

磺基水杨酸-铁(Ⅲ)体系光度分析法测定维生素C的研究

磺基水杨酸与Fe(Ⅲ)在pH 2.00～3.00的溶液中形成紫红色磺基水杨酸合铁(Ⅲ)配离子,维生素C在酸性条件下的还原性,可将Fe(Ⅲ)定量还原为Fe(Ⅱ),使Fe(Ⅲ)-磺基水杨酸体系的颜色退去,其吸光度降低值与维生素C含量在一定范围内呈良好的线性关系,据此提出了测定维生素C含量的新方法.对影响体系吸光度的不同变量和参数进行了研究和选择.方法线性范围为2.0×10-6～1.2×10-4 mol/L,检出限为1.46×10-6 mol/L,回收率为97.8%～100.4%.该方法简单、灵敏度高、选择性好,用于橙汁、蔬菜中维生素C含量的测定,结果满意.     

离子选择性电极法测定牙膏中氟含量研究

使用氟离子选择性电极,通过加入TISAB缓冲液控制测定条件,利用电位分析法,完成对牙膏中游离及可溶性氟离子含量的测定,方法检测范围1×10-1mol/L～1×10-6mol/L,回收率为99.5%,操作简便,结果可靠,值得推广。     

水中溴离子含量测定方法的研究

用溴酚红分光光度法和离子选择性电极法测定水中溴离子的含量。结果表明,分光光度法适用于低浓度(1.2×10-6～2.4×10-5mol/L)溴溶液的测量,对于温度、显色时间等条件都有一定的要求;离子选择性电极法适用于溴离子浓度较大的溶液(10-3～10-1mol/L),除温度外,干扰离子Cl-、CO23-和SO24-对溴离子电极电位影响不大,具有外界环境影响小、方便携带、结果易得等特点。对于一些野外需要及时得到分析测试结果的研究工作,离子选择性电极法具有的优势更为明显。     

测定烟酸类药物的全固态漆酚树脂传感器研究

研制了一种新型的漆酚树脂为载体的全固态电位型传感器 ,用以测定烟酸类药物。其Nernst线性响应范围为 1 .0× 1 0 -2 ～ 6 .0× 1 0 -6 mol/ L,斜率为 5 7.0 ,检测限为 2 .5× 1 0 -6 mol/ L。此传感器响应迅速 ,重现性好 ,稳定性好 ,用此传感器测定烟酸类药物的含量 ,结果与药典法相符。     

Pt/H_xMoO_3电极上甲醇的催化氧化

铂电极在c(K2 PtCl6) =2 .5× 10 -3 mol/L、c(Na2 MoO4 ) =0 .0 5mol/L、c(H2 SO4 ) =0 .5mol/L的溶液中 ,电位为 +1 1～ - 0 2V(vs.SCE) ,以 2 0mV/s的速度循环扫描 10min ,可制得一种Pt/HxMoO3 电极。用循环伏安和电位阶跃方法研究了在所制备电极上甲醇的氧化。实验结果表明 ,所制备电极对甲醇的氧化有催化作用 :(1)氧化电位比在Pt/Pt电极上降低 0 12 5V ;(2 )氧化电流为Pt/Pt电极的 6倍。讨论了Pt/HxMoO3 电极对甲醇氧化的催化机理。     

甲氧苄啶的电化学行为研究及伏安法测定

将裸玻碳电极在0. 2 mol/L NaH_2PO_4-Na_2HPO_4溶液中于+1. 7 V恒电位处理400 s后,得到电活化玻碳电极(EGCE)。以EGCE为工作电极,研究了缓冲溶液、pH、富集时间、富集电压和扫描速度对甲氧苄啶(TMP)测定的影响。结果表明,EGCE对TMP有较高的电化学响应。通过差分脉冲伏安法测试,TMP的氧化峰电流与浓度分别在1. 25×10~(-7)～3. 0×10~(-5)mol/L、3. 0×10~(-5)～1. 0×10~(-4)mol/L范围内呈良好的线性关系,检出限为8. 2×10~(-8)mol/L(S/N=3)。该方法操作简单、快速,用于检测TMP的重现性和稳定性好。     

杯芳烃修饰主客体化学传感器研究——对甲酚的测定

以C—十一烷基间苯二酚杯 (6 )芳烃作为主体分子 ,修饰玻碳电极上制成的一种主客体化学传感器 ,并用其对溶液中的客体分子———对甲酚进行测定。该电极具有良好的选择性 ,对 5 .0× 10 -5～2 .0× 10 -3 mol/L的对甲酚具有很好的线性响应 ,检测下限为 3.0× 10 -5mol/L ,同时对修饰前后玻碳电极的表面状态进行了研究     

壳聚糖膜的研制

研究了壳聚糖膜的制备方法和性能 ,探讨了壳聚糖溶液成膜的最佳工艺条件。用 0 .5 2mol/L醋酸、3 .5× 1 0 - 5 mol/L壳聚糖溶液、0 .2 5mol/L氢氧化钠、0 .40mol/L乙醇制备的壳聚糖膜抗拉强度为 749.2 3 5N /m ;0 .1 7mol/L醋酸、2 .5× 1 0 - 5 mol/L壳聚糖溶液、0 .75mol/L氢氧化钠、0 .6 0mol/L乙醇制备的壳聚糖膜透气性为 2 95 .2 3 5ml/min     

碘化钾-Cd(Ⅱ)-罗丹明B离子缔合分光光度法测定土壤中微量镉

将0. 5 g土壤进行消解,采用碘化钾-Cd(Ⅱ)-罗丹明B离子缔合分光光度法测定土壤中微量镉,最佳反应条件:加入2 m L浓度1 mol/L H2SO4,20%碘化钾-抗坏血酸溶液3 m L,显色40 min,在波长588 nm处测定离子缔合物吸光度。结果表明,Cd(Ⅱ)浓度在0. 25～2. 0μg/m L范围内符合郎伯-比尔定律。本方法测定结果相对标准偏差小于2%,方法检出限2. 1μg/kg,加标回收率98. 90%～100. 60%。实验表明,校园内土壤镉含量0. 035～0. 050 mg/kg范围内,几乎无金属镉污染。     

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。